Happy tax year

Today is the start of the new tax year in the UK and to celebrate the Institute for Fiscal Studies recently published a nice little piece outlining the impact of the inflation indexation of tax thresholds (here). As the IFS points out, the UK routinely uprates the cash value of tax thresholds in line with inflation, unlike many other countries. This process dates back to 1977 when two backbench MPs introduced a process forcing the government to automatically uprate thresholds in what became known as the Rooker-Wise Amendment. This makes a lot of sense: Without such indexation as wages rise in line with inflation, so ever more people at the lower end of the income scale would be dragged into higher tax brackets.

But the IFS notes that across many tax categories this automatic uprating has not taken place for a number of years. Two of the most interesting examples are fuel duties which have not increased in cash terms since April 2010 whilst working-age benefits have been frozen since 2015-16. At a time when governments around the world are trying to curb vehicle emissions it does seem rather odd that the UK is not taking the opportunity to take the moral high ground by raising emissions taxes. Consumer prices have risen by 16% since the start of 2011 which would add around 10p to a litre of diesel (7.5%). Obviously, drivers will not complain that the real value of fuel taxes has declined over the last 9 years but it does seem at odds with the government’s self-professed green credentials. We can view this move in one of two ways: It is an overtly political move to curry favour with motorists or it is an attempt to reduce the regressive effect of such taxes.

Being charitable, we should perhaps assume the latter option in an effort to redress the effect of a freeze in the cash value of working age benefits, which obviously means a decline in real terms. But as the IFS put it, “the government might believe that benefits should be more or less generous, but the extent of any change in generosity should be thought through and justified, not the arbitrary and accidental result of what the rate of inflation turns out to be.”

The IFS has also identified a growing trend of instances where thresholds are maintained in cash terms and only uprated when the government believes it to be necessary. Most of these instances really only affect those at the upper end of the income scale and whilst the vast majority of taxpayers will not shed any tears for the better paid members of society, they do illustrate how arbitrary manipulation of tax thresholds can result in some strange outcomes which may impact on work incentives.

One such is the £100k threshold at which the personal tax allowance is progressively withdrawn. Anyone earning below this amount is entitled to a £12.5k tax-free allowance but for every £2 of income above £100k the tax free amount is reduced by £1. One result of this is that those earning between £100k and £123.7k are taxed at a marginal rate of 60% (i.e. they keep just 40p out of every £1 they earn thanks to the allowance taper). Yet more bizarre is that those earning between £123.7k and £150k are once again subject to a lower marginal tax rate of 40% (above £150k the marginal income tax rate rises to 45%). “Oh dear, how sad, never mind” you may say. But there are now 968,000 taxpayers’ earning more than £100k – an increase of more than half since 2007-08, who have been dragged into the net due to the failure to index the threshold.

That said, higher taxes on the better off in society have been used to fund an extension of the zero-tax threshold for the less well paid. In fiscal year 2007-08 (the last year before the financial crisis) those earning £10,000 paid an average tax rate of 13.1% (income tax plus National Insurance Contributions). The government’s stated policy of taking the lower paid out of the tax system altogether means that someone earning this amount today pays an average tax rate of only 1.6%. As the chart suggests, the average tax schedule has clearly shifted to the right compared to 2007-08, illustrating the reduction in tax liability of the less well paid. The curve is also lower than it was in 2007-08 for incomes below £100k, so most people pay less tax, but it rises sharply thereafter, and those earning £120k are paying more.

But the true marginal tax rate is not merely made up of the amount levied on income – we have to account for the withdrawal of social welfare entitlements, and those lower down the income scale are in the line of fire. For example, those earning more than £50k per year have to pay back some of their Child Benefit in the form of extra income tax. If they earn between £50k and £60k and have one child, they face a marginal income tax rate of 51% but if they have three children their marginal income tax rate is 65%. Again, this threshold has remained unchanged for some years which means an increasing number of people are likely to run into this problem.

However, one of the more bizarre quirks is the reduction in the pension annual allowance for high-income individuals. The first £40k of pension contributions is free from income tax but those whose income (excluding pension contributions) exceeds £110k face a tapering in their tax free pension allowance. Without going through the details (they are outlined in the IFS paper), the upshot is that someone earning £150k (including pension contributions) can put £40k into their pension without incurring extra taxation but someone whose total income (including pension contributions) is £210k finds that their tax free allowance is reduced to only £10k. More bizarre still is that the likes of senior doctors, whose generous defined benefit pension schemes result in contributions exceeding £40k, can end up facing marginal tax rates of more than 100%. I was recently made aware of instances where such doctors are not prepared to work beyond a certain point because they pay more tax than they earn (obviously, they could offer their time for free but they could equally well enjoy an evening at home if they are not getting paid for it).

Although some of the examples highlighted here are extreme cases, they illustrate how an ill-designed tax system can result in high marginal tax rates that act as a disincentive to work. And the more people are dragged into the tax net due to the absence of indexation, the greater is this effect. A good tax system should meet five basic conditions: fairness, adequacy, simplicity, transparency, and administrative ease. A lack of inflation indexation undermines all of them.