IN SEARCH OF THE GREEN PARTY’S £500BN MISSING TAX FIGURE

Jenny Jones, the Green Party peer, appeared on TV earlier stating that HMRC had failed to collect £500bn from the wealthy.

Where, if anywhere, does this figure come from?

The superficial reaction is simply to say the number is made up. But, with respect, I don’t think it entirely is.

It is likely that the source of the £500bn likely source is everyone’s favourite tax publication… HMRC’s “tax gap”. (I know you have a secret annual subscription on ‘auto-renewal’ 😉 )

This the estimate of the difference between what should be paid in tax and what is actually collected.

HMRC’s latest estimate puts that gap at £46.8bn for 2023–24 (published June 2025), and the department says the figures are estimates that are uncertain and revised over time.

However, using HMRC’s further workings, adding the “Total tax gap” row from 2010-11 through 2023-24 gives about £500.7bn.

So, one might therefore conclude that Jones’ figure is basically a cumulative 14-year total, rounded to “£500bn”… not a one-year figure.

[That said – there are earlier years that could have been included making the total aggregate £700bn. So, it’s a surprise that, if my method is correct, they haven’t gone the whole hog!]

But this gives us a slight problem.

This is because HMRC’s own breakdown does not show the bulk of the missing tax coming from the richest.

In the latest figures, small businesses account for the biggest share of the tax gap at 60%, while “wealthy” individuals account for 5%.

Using the same HMRC customer-group table across 2010-11 to 2023-24, the cumulative “wealthy” line comes to about £24.8bn out of the £500.7bn total, versus about £232.4bn for small businesses. So the £500bn figure comes from HMRC, but saying it is mostly unpaid tax from the rich is not what HMRC’s own published breakdown shows

Additionally, HMRC says the tax gap does not include BEPS/profit-shifting arrangements that cannot be addressed under UK law. In other words, things that a tax adviser or lawyer might say are not avoidance… but about which the public is not likely to be quite so accommodating.

So, the real story here is that Britain is still likely losing tens of billions in unpaid tax. But if politicians are going to wield a £500bn headline, they should be honest about what it is…

… a cumulative tax-gap figure built up over years, not a single missing fortune…

… and that the shortfall does not solely sit at the feet of the super-rich