Ben Chu on corporation tax incidence

Posted by Christie Malry on August 17, 2015 at 9:24 pm

Ben Chu has written a muddled piece on corporation tax incidence. Because he'd prefer to be snarky with me than get to the heart of why a chartered accountant thinks his article muddled, here's a fuller exposition of everything that's wrong with his article. Ben, you're welcome.

“Guns don’t kill people, people kill people,” argue opponents of gun control in America. Tax economists have their own, analogous, rallying slogan: “Companies don’t pay tax, people do.”
The key word here is “incidence”. What these economists mean is that we should think carefully about who, ultimately, is going to end up bearing the cost of a proposed tax.

So far so good. It's well-known that the incidence of corporation tax falls upon some mixture of investors (through lower dividends), workers (through lower wages), suppliers (through lower demand) and customers (through higher sales prices).

Many on the left, such as supporters of the Labour leadership contender Jeremy Corbyn, are in favour of raising corporation tax so companies pay their “fair share” to the Treasury’s coffers. But companies are not individuals with a taxable income in their own right. All their net income, or profits, must in the end flow to the firms’ shareholders. So, in theory, it is shareholders who ultimately bear the costs of corporation tax. And that, by the way, includes all of us who have a pension invested in company shares.

But like a medicine ball dropping on a water bed, the cost of corporate taxation bulges out in other areas too. The Institute for Fiscal Studies points out that corporate taxes, as well as often leading to smaller dividends to shareholders, can be passed on in the form of higher prices for consumers and lower employment by that firm than would otherwise have been the case.

No, it's not "in theory" the case that shareholders bear the cost of corporation tax. At least not according to any theory that someone who has looked at the evidence could support. Anyone who overlooks either or both of the higher consumer prices or lower employee wages outcomes is burying their head in the sand in the face of academic evidence.

It’s the latter effect that prompts many to label employers’ national insurance contributions (the contributions that firms must make to HMRC on behalf of each employee on the payroll) a “jobs tax”.

What has employers' national insurance got to do with corporation tax? Corporation tax is based on taxable income. Employers' national insurance is based on staff wages. Why would anyone presume that the incidence of corporation tax would be the same as the incidence of employers' national insurance?

The proposed European Union tax on financial transactions is also criticised on incidence grounds. Critics claim it will not ultimately be paid by the hated banks who perform the transactions, but will merely be passed on to the innocent users of the banks’ services.

Again, the proposed tax on financial transactions is calculated on a completely different basis to corporation tax. Why would anyone presume that the incidence of corporation tax would be the same as the incidence of the proposed tax on financial transactions?

The theory of tax incidence is the proper guiding principle for politicians, civil servants and anyone in the debate about tax. It is naïve to regard private companies as some kind of a magic piñata which can be endlessly (and costlessly) beaten with a tax stick in order to fund public services and welfare payments.

Nevertheless, it is also naïve to veer to the other extreme and interpret the insight of tax incidence as a clinching argument against any corporate taxation. For a start, we should be wary of assuming we know what the incidence of a given tax will be.

The dichotomy presented is false. It is very important to understand, as best as we can, what the incidence of corporation tax is. Otherwise, we may find we're trying to make a company pay its "fair share" but are only making the company's workers and the company's customers pay instead. Having established corporation tax incidence, we can then take a view on whether more or less corporation tax is desirable.

The Independent’s campaign on the airport VAT scam inadvertently highlighted this danger. Our reporters have drawn public attention to the fact that the benefit of the VAT tax exemption for goods sold at airports to people travelling outside the European Union is often effectively pocketed by the vendors, rather than being passed on to customers.

Why would anyone presume that the incidence of corporation tax would be the same as the incidence of VAT?

In a truly competitive airport retail market, that benefit ought to flow directly to customers in the form of lower prices. But retail markets in airports, it would appear, are not truly competitive. Believe it or not (and many on the right have trouble accepting this fact) this is sometimes the case outside airport terminals too.

So retail markets in airports aren't competitive? Duh. Customers are a captive market, with no choice between shops.

Outside the confines of airport security, these constraints don't apply. Customers have a choice of suppliers. They are flexible about when to take delivery. They can more easily compare prices between suppliers. There's simply no reason at all to presume that markets as a whole behave like they do within airports. "Sometimes the case" may be right. But Ben presents no evidence of which of the two models for markets is most appropriate.

There are times when taxes on companies are justified on other grounds. One instance is when they are used to target “externalities”, or activities that impose economic costs on society in general. The primary purpose of a financial transactions tax, as originally proposed by the Nobel Laureate James Tobin in 1972, was not to raise revenue but to “throw sand in the wheels” of currency speculation, which he held to be responsible for harmful volatility in nations’ exchange rates.

It is true that under the EU Commission’s version of the tax, financial trading in bonds, shares and financial derivatives will be made less profitable for banks. And, yes, they may well attempt to pass on the cost to customers (asset managers and hedge funds) to preserve their profit margins.

But it should also reduce the gargantuan volume of socially useless inter-bank trading of financial securities that takes place by rendering it less lucrative. And as far as the banks’ customers are concerned, it would be a very good thing if it results in less demand for their trading services. All the available evidence suggests that the ultimate owners of shares would benefit from less churn of their portfolios by their designated asset managers.

The UK’s bank levy is another example of a corporate tax that is justified on economic externality grounds. This levy taxes banks based on the size of their balance sheets. The Chancellor, regrettably, watered this down in his most recent Budget to please the powerful banking lobby. But nevertheless, the existence of this tax helps to compensate the state for the fact that these institutions are widely seen as “too big to fail” and receive a de facto lower funding cost in the markets as a result of the assumption that the state would have to rescue them if they got into trouble again. The levy helps to defray the incentive for the managements of these financial institutions to grow their balance sheets still further to capitalise on the de facto state subsidy.

What is the externality that corporation tax is aiming to address? Ben doesn't want to answer this question. But without an answer, this section is a load of wibble. Consider the following argument: "Some foods cause cancer. Quinoa is a food. Therefore quinoa causes cancer". This argument, logically equivalent to Ben's, demonstrates why Ben's discussion - while interesting - doesn't help justify corporation tax.

Finally, there are practical reasons for taxing companies directly, rather than recouping the money from individuals when they receive the corporate income as dividends. As the IFS itself argues, corporation tax makes sense because it’s a way of taxing the dividends due to foreign owners of shares in UK-listed companies. It would otherwise be very hard – probably impossible – for the Treasury to tax this income. Given that more than half of the shares in UK-listed companies are now held abroad, up from 10 per cent in the 1960s, that’s clearly a significant advantage. And in that context, George Osborne’s apparent desire to push down the UK’s rate of corporation tax until it disappears altogether doesn’t look so smart.

Well, it depends. Suppose academic research established that the incidence of corporation tax was entirely on workers and customers. In this case, investors wouldn't care what the level of corporation tax is, because they don't pay it. Somebody else does. We might think we're getting £x bn from foreigners. But in fact it's workers and customers who are paying.

Alternatively, suppose academic research established that the incidence of corporation tax was entirely on investors. In this case, investors would mind very much about the level of corporation tax and would make prospective investment decisions based on their post-tax income. Lower investment in the UK means lower growth and fewer jobs in the UK and, correspondingly, higher growth and more jobs somewhere else. This becomes a political calculus: can politicians justify a higher actual tax take combined with lower growth and employment compared to what might have been?

In truth, corporation tax incidence isn't so black and white. It falls on investors and it falls on workers and it falls on customers. The balance is subject to debate. Early academic work (Harberger 1962) suggested that the lion's share fell on investors. However, Harberger's work failed to take account of the mobility of international capital. Subsequent analyses, including Arulampalam et al 2010, find that workers pay most of cost of corporation tax. Ben fails to present a convincing case - or indeed any case at all - why we should reject the findings of Arulampalam's paper. Why take the incoherent bumblings of a journalist, one a university background in history, over the careful study of academic economists? I think we should be told.

“Companies don’t pay tax, people do,” is certainly the right starting point for any debate about corporate tax. But it shouldn’t be the last word.

This conclusion is bonkers. Of course only people pay corporation tax. So it would be bizarre to view this as the last word in any debate on the tax. The last word hinges on what we think we know about the proportion in which different groups of people - investors, workers and customers - share the burden of corporation tax.

You'd have to be particularly sadistic and/or stupid to argue for maintaining the corporation tax rate while ignoring the burgeoning body of academic evidence that it is borne by workers. But that's just what Ben does. As I said originally, this is a muddled piece that is unworthy of a national newspaper.

Grandson of CCCTB: the stubborn policy that refuses to die

Posted by Christie Malry on May 27, 2015 at 4:47 pm

There’s a renewed buzz around the European Common Consolidated Corporate Tax Base (CCCTB). A new Commission seems to have dusted off the mothballed plans for CCCTB and is actively considering how they might be put into practice in the EU as a solution to perceived widespread corporate tax avoidance.

Our current approach to taxation is to allow each country to set its own rules for what gets taxed in their borders. A system of bilateral treaties aims to get countries to ‘play nicely’ together. Via these agreements we end up such principles as transfer pricing, which seeks to ensure that group companies transfer goods and services to each other at something approximating to a market price, had those goods/services been sold by a third party. The system doesn’t work perfectly, for sure, but it keeps most of the countries happy most of the time.

But not enough countries happy enough, so CCCTB is back on the table. CCCTB would, in the EU at least, sweep aside this approach to tax and its bilateral treaties. In its place, we would get agreement that a tax base for a multinational company operating in a group of countries would be agreed between them based on common principles and each country’s portion of this tax base shared out according to a formula. The idea is that multinational companies would no longer be able to transfer profits from high tax countries to low tax countries using artificial service contracts that fly under the radar of thinly-resourced national tax authorities.

However, there’s a fundamental problem with CCCTB: It Won’t Work.

It won’t work for three reasons. However, it’s my belief that any one of these reasons would, on their own, be enough to sink CCCTB. Taken together, it’s testament to the political amnesia that a new Commission can bring that the EC is even considering this at all.

For a common tax base to work, it has to be global. But CCCTB is only a local tax base

With CCCTB being a tax base for Europe only, it will require multinational companies to prepare a subconsolidated tax base for Europe. Countries outside this tax base will continue to be taxed as currently. CCCTB may ‘solve’ perceived profit shifting within Europe but does nothing to prevent the same tricks being used to shift profits between Europe and non-Europe. Arguably, this is even worse, because employment that is currently ungainfully employed in Luxembourg and the like might end up in non-European tax havens.

CCCTB as currently devised would be an expensive add-on for companies and would only incentivise naughty companies to take their naughtiness elsewhere.

For a common tax base to work, it has to be mandatory. But CCCTB is optional

As an optional method of taxing multinational companies, CCCTB will only be picked by those with something to gain from it, or at least with nothing to lose. This will leave European countries having to each fund two systems of taxing multinational companies, with the company getting to pick the one that works best for it. Meanwhile, smaller businesses will have no choice but to stick with their current method of taxation.

It’s hard to imagine how this could be fairer than  our current approach where all companies are taxed on the same basis. CCCTB will allow multinational companies to opt for a different way to be taxed if it suits them. This dual approach can only fuel the sense of injustice.

The formula can never hope to encapsulate public views of fairness

It’s apparent that the public feels that the current approach to taxing multinational companies is unfair. This sense of unfairness is heightened by cases where a company reports high profits in its accounts but pays small amounts of tax, even where there are good reasons for this.

The current approach to taxing multinational companies is to tax each subsidiary separately in the countries in which it has a ‘permanent establishment’. Although some subsidiaries’ profits are eliminated upon consolidation, there is a loose link between the accounting results of the consolidated group and the taxable results of the subsidiaries. Financial reporting standards require companies to account for the difference between accounting book values and tax book values by charging or crediting a notional tax item called ‘deferred tax’. In addition, companies must explain why the total tax charge (current tax plus deferred tax) as a percentage of reported pre-tax profits differs from the statutory tax rate(s) faced by the company. These disclosures aren’t always done well and they’re not well understood even when they are. But they are part and parcel of the reporting requirements of multinational companies.

CCCTB would change this. Instead of calculating the tax base from the local accounting numbers, adjusted for tax reasons, the tax base will be a portion of the European tax base, according to some formula. The current proposal is that the formula will be based upon external revenues, assets, employee numbers and employee salaries.Clearly, the formula will produce different results than the current approach. It’s supposed to, after all. What’s less clear is whether the formula can reflect public perceptions of (a) what the ‘true’ economic performance in each country is, and (b) what is fair.

As Andrew Jackson has shown, there are concerns about how the proposed CCCTB formula will operate. Using external revenues may discriminate against shared service divisions. Using assets may discriminate against countries with older subsidiaries with fully depreciated assets. Using employee numbers may discriminate against countries with contracted labour. Using employee salaries may discriminate against countries with low unit labour costs. Unless these factors can be finessed by tweaking the formula, it’s unlikely CCCTB can hope to address the lack of public confidence in the tax system.  However, the complexity of the formula is in itself likely to undermine public confidence in the tax system.

These issues are a direct consequence of the design of CCCTB. They cannot simply be magicked away by a clever formula. The greater the number of links in the chain between local performance and local taxation, the greater the opportunity for public angst about tax.

As an aside, be very sceptical of anyone arguing in favour of unitary taxation who doesn’t tell you which formula they intend to use. They are not solving the problem of multinational company tax; they are merely redefining the problem in terms of another problem. And this latter problem is - I argue - insoluble.


It is my belief that each of these problems would be enough to sink CCCTB. Taken together, it’s not difficult to see why CCCTB faced significant opposition during its earlier development.

None of these problems has been addressed. CCCTB has been brought back to life, but the problems which killed it off still course through its veins. They will, once more, kill it off.

Gay cakes

Posted by Christie Malry on May 19, 2015 at 2:34 pm

In which of the following situations can the business owner refuse service without being sued for discrimination?

1. Two men order a wedding cake with "For Chuck and Dick" on the top.

2. A man and a woman order a wedding cake with "For Chuck and Dick" on the top.

3. A straight man orders a cake with "Gay marriage is great" on it.

4. A gay man orders a cake with "Gay marriage is great" on it.

5. A straight man orders a cake with "Hitler is a hero and the Holocaust was justified" on it.

6. A gay man orders a cake with "Hitler is a hero and the Holocaust was justified" on it.

If it's the slogan that's the problem, not the person seeking service, how can it be discrimination?

Um, no

Posted by Christie Malry on April 13, 2015 at 11:33 pm


The problem they [right wingers] face is this. If you won’t advocate sensible reform against your own interests you can’t expect to be listened to when you advocate sensible reform for them.

This is just silly.

An argument stands or falls based on two things: facts and whether the policy is supported or refuted by those facts.

The strength or weakness of an argument is unrelated to who makes it and whether it's in their own interest for them to make it. Jolyon makes a logical fallacy here, a form of ad hominem.

For sure, being predisposed to a policy might make the proposer likely to overstate upsides, downplay downsides and/or skew evidence in their favour. So show where they've done that, instead of smearing them.

Ritchie caught lying again

Posted by Christie Malry on April 12, 2015 at 2:41 pm

He's caught bang to rights:

There are three things to say about Osborne’s long term economic plan.The first is he did have one. It was based on imposing austerity. It failed. We had a recession.

This just isn't true. A recession is defined as two successive quarters of negative growth. And we simply haven't had two successive quarters of negative growth at any time in this Parliament.


Non-dom dynamics

Posted by Christie Malry on April 9, 2015 at 6:12 pm

One day on, and we’re still reading total hogwash about non-doms. Jolyon started it, with his ill-conceived back-of-a-fag-packet calculations that started to unravel almost as soon as he had pressed publish. Then campaigners changed tack, arguing that it was never about money but was about fairness instead. The exercise of how it’s “fair” to change non-dom taxation in a way that might reduce overall tax revenues, leaving ordinary people to pay more, is left to the reader. The indomitable non-dom campaigners are back again today, claiming ‘hell no, they won’t go’ in what might be a case study in missing the point.

Enough, already. This post aims to set out the dynamics of answering the question of what would be the impact on tax revenue of abolishing the non-dom remittance basis.

First, we need to establish just what the non-dom basis is. Thanks to the CIOT, there’s a handy primer to the law here, and I suggest you go refresh your memory as it’s a good summary.

So, Labour’s policy is to prevent those who currently claim the remittance basis of taxation in respect of their non-UK income from doing that in future.

Currently we get:


Where N is the number of non-doms claiming the remittance basis, IncUK is their UK taxable income, TR is the tax rate, Unremitted is their unremitted foreign income, Remitted is their remitted foreign income, RBC is the remittance basis charge and multiplier is a variable to reflect their economic impact on the rest of the economy. [Of course, you can’t actually multiply N by the average income for each non-dom. More strictly, you should be summing the bit in brackets individually across the population N. But it’s easier to understand if it’s presented in this way.]

Labour would move to this basis:


Where IncForeign  = Unremitted + Remitted. I’ve put some redundant terms in each equation to make them easier to compare.

Jolyon’s analysis can be summarised, roughly, as follows:

  • N won’t change much because previous changes were accompanied by small behavioural responses.
  • He ignores the max(UK-Foreign) side of the tax rate calculation using TRUK instead, although this may be because people who currently pay the remittance basis charge do so to avoid a UK tax charge that would otherwise exceed the remittance basis charge. Still, it’s important to calculate these things properly. Guido called him on this yesterday.
  • He ignores RBC altogether. He has claimed on Twitter that its impact would be relatively insignificant.
  • And he ignores multiplier altogether.

He argues that it’s OK to simplify it like this because the behavioural impact is uncertain, so we can smear its impact across all the other variables to arrive at an overall approximation of, he says, £1 billion or more.

Don’t ignore the remittance basis charge

But omitting RBC is a howler. He’s trying to calculate the steady state impact of abolishing the remittance basis altogether. Currently, only a handful of people pay the charge as it only applies if you’ve been living here for some time. But if all 49,000 people who currently claim the remittance basis had to pay the remittance basis charge, even at its lowest level (£30,000), this would bring in £1.47 billion. And Labour just abolished the remittance basis, so that represents a loss to the Treasury of more than Jolyon claims would be brought in by changing the way non-doms are taxed.

Don’t overlook the spending power of rich people

Omitting multiplier is also a howler. Anyone who is prepared to (eventually) pay the remittance basis charge is rich. Richer than you or I can imagine. Rich people tend to have lots of money but no time, so they use their money to pay people who have lots of time but not so much money to do things for them. They hire drivers, cleaners, nannies, executive assistants. And they spend money on cars, houses, golf club memberships, restaurants and football clubs - both tickets to go see them play and, in some cases, the clubs themselves. You can turn up your nose at this spending if you like. But it is undeniable that rich people have an impact on the economy that goes beyond the tax that they pay to the Treasury. How much? I don’t know. But my instinct would be that multiplier is a positive number and that it’s quite big.

The biggest UK tax risk isn’t that non-doms leave, it’s that they never come in the first place

The last howler that’s being repeated by almost every commentator everywhere is in respect of N. When people say ‘they won’t go’, they’re treating N as if it were some sort of constant. But of course it isn’t. People leaving the UK isn’t the only way N can decrease. We’re talking about rich people here, and rich people tend to be older. And old people die. Over time, they will all die. To sustain a future tax income stream from the megarich, we must entice more of them to leave wherever they live now and come to live in the UK. It’s not obvious to me why a very rich person would want to choose the UK over, say, Ireland or Switzerland, when the UK would tax their worldwide income much more heavily than those alternatives. Yes, tax isn’t everything, for sure, but a six-figure tax difference is enough to make someone think twice. When Richard says non-doms won’t be leaving, he’s totally missing the point. The biggest risk to the Treasury isn’t the non-doms who leave. It’s the non-doms of the future who decide never to come.


Even if this weren’t in the run-up to a General Election, this would still remain a political, emotional debate rather than a rational, economic one. But it’s a shame that, in their rush to make a political impact, so many ordinarily sensible people are abandoning reason for headline grabbing rhetoric.

Income, schmincome

Posted by Christie Malry on April 9, 2015 at 12:27 pm

He: “I’m really cross about all this non-dom stuff. It’s an outrage!”

She: “What’s that?”

He: “Non-doms get a massive tax break so they don’t have to pay tax like we do. It must be stopped!”

She: “Go on”

He: “We have to pay tax on all our income.”

She: “And non-doms don’t?”

He: “No, they pay tax on all their income too.”

She: “So what’s all the fuss about?”

He: “Non-doms don’t have to pay tax on their schmincome.”

She: “What’s schmincome?”

He: “Schmincome is income they earn in another country.”

She: “Oh. And you do have to pay tax on schmincome?”

He: “You bet I do. It’s completely unfair!”

She: “But can they use schmincome as income?”

He: “Well, they can. But if they do turn schmincome into income then they have to pay tax on it.”

She: “OK. I’m still struggling to see why that’s unfair on you.”

He: “Because I have to pay tax on schmincome and they don’t!”

She: “So how much schmincome do you have?”

He: sheepishly “Well… none, actually”

She: “Er…”

He: “But if I did have schmincome, I would have to pay tax on it. It’s disgusting and indefensible that they get such preferential treatment…” (cont’d p94)

Shouldn't we extend non-dom status to everyone?

Posted by Christie Malry on April 8, 2015 at 12:06 pm

Consider the following examples. K, L and M are all UK-domiciled:

  • K’s elderly mother lives in Canada. K regularly goes to visit her to check that she’s OK. K retains a Canadian bank account with a modest amount in it to cover incidental expenses while visiting and to be able to pay for emergency care if she becomes ill while K is in the UK. The account earns interest.
  • L hopes to retire to Brazil in several years’ time. Because property prices are currently at an all time low, L has bought a house there now and has rented it out. All money is being retained in Brazil to cover possible emergency costs.
  • M works for a multinational company and has just returned from a two year posting to the US. M’s package in the US included a 401K in which there is a five figure sum. M became engaged while in the US and is still undecided whether to make their long-term home in the US or the UK.

In each of these cases, the UK tax system seeks to tax the worldwide income of K, L and M. So the bank account interest, rental income and 401K investment return would be considered taxable for UK purposes, subject to any double tax agreement between the UK and those countries.

Putting to one side the rhetoric about billionaire non-doms, can anyone explain why it would not be fairer to simply ignore K, L and M’s foreign assets altogether? Rather than, as currently, forcing K, L and M to account for their worldwide income and navigate two tax systems that may or may not have treaty provisions to eliminate double taxation?

Still not convinced? Read Robert Maas’s excellent post on the complexities of how UK tax law messes with internationally mobile ordinary people. Wouldn’t it be better, far easier and fairer for ordinary people just to tax everyone as if they were a non-dom?

Should we judge HMRC by process or results?

Posted by Christie Malry on February 18, 2015 at 9:48 am

Imagine two taxpayers. One is a small business. Perhaps an entrepreneur and her husband. The business’s tax affairs are challenged by HMRC and she must go to court to fight her case. After a lengthy case, which is appealed, she wins.

The other is a large multinational. This business’s tax affairs are challenged by HMRC and the multinational must go to court to fight its case. After a lengthy case, which is appealed, it wins.

How would these cases be reported in the media? The SME case would be the tale of a plucky entrepreneur who has had to take time away from her business (and family) to fight an unfair challenge from a faceless government inspector. Whereas the multinational case would be the story of how big business dodges its tax responsibilities and, by employing its vastly superior resources, hoodwinked the tax authorities.

Of course, these are gross simplifications. But it seems - to me, at least - that the idea that HMRC is tough on small business but gives big business an easy ride is a selection bias problem. Everyone knows a family member or friend or friend-of-a-friend who has been taken through the wringer by HMRC. Whereas not everyone knows a tax director at a FTSE-100 company. That means we tend to judge HMRC’s interface with SMEs by its process whereas we judge the interface with multinational business by its results.

HMRC is an organisation that takes money off you. Invariably, it will focus on those areas where it thinks you haven’t paid as much as you should. So any interaction with it is unlikely to be pleasant. Judging HMRC by process will invariably create a negative impression of HMRC, which looks like it behaves badly in its dealings with ordinary people.

Assessing HMRC by its results creates a no-win situation. Either HMRC loses, which makes it look soft on big business. Or it wins, which merely reinforces the idea that big businesses are dirty tax dodgers. Whatever the outcome, tax campaigners can chalk it up as another piece of ‘evidence’ that big business and HMRC are unethical.

A better approach would be to recognise that both the SME and big business narratives are inadequate. We need to assess HMRC by its overall service standards, and business by its overall behaviour, not merely by the narrow parameters of tax investigation process or outcomes. Anything less might produce good stories but inevitably leads to terrible policy.

The impact of cutting taxes on tax avoidance

Posted by Christie Malry on December 18, 2014 at 1:24 pm

the Tories have realised, rather late in the day, that cutting taxes does not in any way end tax avoidance.

This is obviously untrue.

Imagine a country with a tax rate of 20%. And suppose companies are very, very badly behaved. So bad, they use no end of (legal) tax avoidance techniques to dodge half the taxes due. Suppose the cost of this is 1% of their taxable profits.

If the government of that country cut the tax rate to 10%, there would no longer be any need to avoid taxes. Companies would be better off sacking their tax advisors and simply paying the tax due. Because the net cost of doing this would be 10% of (pre avoidance) taxable profits, not the current 11% (yet don't lose sight of the fact that they *should* be paying 21%: the 20% statutory rate plus the 1% they've decided to spend on advisors).

But suppose they keep on paying their advisors to dodge even more tax. Suppose those devilish lawyers manage to produce a 5% effective rate of tax in return for their 1% fee. Then the company would be paying 6% instead of 10% so it would continue to avoid. But the amount avoided is only 5% of taxable profits, not the 10% when taxes were higher.

Lowering the tax rate necessarily reduces tax avoidance because of these two effects. Firstly because it reduces incentives to avoid in the first place. Secondly because it reduces, arithmetically, the level of any avoidance that does taken place.

Making it utterly ludicrous to suggest that cutting taxes doesn't reduce tax avoidance "in any way".