Why is tax avoidance a reason for letting people off tax?

Tax dodging, the Laffer curve, and the 50p rate

The reason given for cutting the 50p rate of tax to 45p was avoidance. It wasn't clearly phrased as such – most of the talk was about how it had raised less money than expected, or had changed behaviour in ways that harmed growth – but that is what it was nonetheless. To many, this will seem strange. "You avoided tax, so we will make you pay less". But it is an integral part of the line of thought that lies behind the cut.

Art Laffer first made the argument that cutting tax rates could boost revenue. The reasoning is broadly that, when the marginal tax rate (the amount you pay on each extra pound earned) gets too high, people start doing things to reduce their taxable income.

The palatable version is that they work less, because an extra hour of work no longer pays as well as it did, and this is probably true; there are certainly anecdotal tales of highly paid consultants turning down work later on in the year to spend more time at home.

The less palatable version is that they avoid more tax, because spending the money and effort required to set up a limited company, be paid "overseas", or funnel your income through a Swiss bank account in the name of your dog becomes more worthwhile the more it saves you.

Both of these "behavioural changes" are factored in to the Laffer curve, the rough prediction of how much revenue will be gained at various marginal tax rates. HMRC produced three such curves, each based around a different "taxable income elasticity" (TIE), a measure of how much an individual's behaviour changes given the tax rate:

They based their analysis around a TIE of 0.45 (a figure basically plucked from thin air – HMRC admit the evidence to choose is "extremely limited", and the studies they cite range from -0.6 to 2.75), which showed a peak of revenue at around 48 per cent. Quite why this then led the Chancellor to cut the rate to three per cent below that is unclear. If he wanted to raise revenue, his own analysis is showing that he's done it wrong.

The problem is, one thing which affects the TIE is the ease with which one can avoid tax. Make tax avoidance harder, TIE goes up, and the peak revenue rate increases. In fact, given the anti-avoidance measures announced at the budget yesterday, TIE will already be higher than it was at the time of the analysis, boosting the argument for keeping the 50p rate.

There is one massive category of avoidance which can't be cited as a reason for cutting the rate, however. The HMRC's stats show that £6.6bn less income was declared in 2010-11 due to it being "forestalled" – paid the year before, so as to take advantage of the lower rate. This is avoidance on a massive scale (Richard Murphy points out that it is £1.6bn more than the estimation for all tax avoidance in 2011), yet, contra Tim Worstall, it has no bearing on the decision on whether or not to cut the rate, because it can only ever be done once. 

By cutting the tax so early in its life, Osborne has ensured that we make the decision unable to know the full effect of cutting it. We can guess at how much will have been raised for the 2011-12 tax year, when forestalling was harder (although not impossible, and HMRC warn that it "continues to reduce revenues in 2011-12 and beyond"), but by the time we know for sure, it will be too late. The 45p tax will be in, and there won't be a "normal" year of the 50p rate to compare it to.

Tax dodging is an emotive issue. Credit: Getty

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Photo: Getty Images
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What do Labour's lost voters make of the Labour leadership candidates?

What does Newsnight's focus group make of the Labour leadership candidates?

Tonight on Newsnight, an IpsosMori focus group of former Labour voters talks about the four Labour leadership candidates. What did they make of the four candidates?

On Andy Burnham:

“He’s the old guard, with Yvette Cooper”

“It’s the same message they were trying to portray right up to the election”​

“I thought that he acknowledged the fact that they didn’t say sorry during the time of the election, and how can you expect people to vote for you when you’re not actually acknowledging that you were part of the problem”​

“Strongish leader, and at least he’s acknowledging and saying let’s move on from here as opposed to wishy washy”

“I was surprised how long he’d been in politics if he was talking about Tony Blair years – he doesn’t look old enough”

On Jeremy Corbyn:

"“He’s the older guy with the grey hair who’s got all the policies straight out of the sixties and is a bit of a hippy as well is what he comes across as” 

“I agree with most of what he said, I must admit, but I don’t think as a country we can afford his principles”

“He was just going to be the opposite of Conservatives, but there might be policies on the Conservative side that, y’know, might be good policies”

“I’ve heard in the paper he’s the favourite to win the Labour leadership. Well, if that was him, then I won’t be voting for Labour, put it that way”

“I think he’s a very good politician but he’s unelectable as a Prime Minister”

On Yvette Cooper

“She sounds quite positive doesn’t she – for families and their everyday issues”

“Bedroom tax, working tax credits, mainly mum things as well”

“We had Margaret Thatcher obviously years ago, and then I’ve always thought about it being a man, I wanted a man, thinking they were stronger…  she was very strong and decisive as well”

“She was very clear – more so than the other guy [Burnham]”

“I think she’s trying to play down her economics background to sort of distance herself from her husband… I think she’s dumbing herself down”

On Liz Kendall

“None of it came from the heart”

“She just sounds like someone’s told her to say something, it’s not coming from the heart, she needs passion”

“Rather than saying what she’s going to do, she’s attacking”

“She reminded me of a headteacher when she was standing there, and she was quite boring. She just didn’t seem to have any sort of personality, and you can’t imagine her being a leader of a party”

“With Liz Kendall and Andy Burnham there’s a lot of rhetoric but there doesn’t seem to be a lot of direction behind what they’re saying. There seems to be a lot of words but no action.”

And, finally, a piece of advice for all four candidates, should they win the leadership election:

“Get down on your hands and knees and start praying”

Stephen Bush is editor of the Staggers, the New Statesman’s political blog.