HM Revenue and Customs (HMRC) does not know how much tax billionaires pay despite their small number and large finances, MPs revealed today. 

The public accounts committee said that HMRC “can and must” do more to understand and explain the tax contribution of Britain’s wealthiest.

Its report, focusing on correctly taxing the rich, found that HMRC “does not know how many billionaires pay tax in Britain or how much they contribute overall.” 

It urged the body to publish a clear plan to increase tax yield from wealthy individuals, both domestic and offshore.

Currently, HMRC collects only the data needed to administer existing tax rules, not information on wealth. 

The report suggested HMRC could start by cross-referencing its data with public sources like The Sunday Times Rich List to identify any gaps.

The committee also said HMRC should improve its ability to target risk through better data analysis, AI tools, and specialist staff.

MPs questioned the credibility of HMRC’s estimated £1.9 billion tax gap for wealthy individuals – and a £0.3bn offshore gap — especially given that Britain’s residents held £849bn of assets offshore in 2019.

Although compliance activity brought in £5.2bn last year, up from £2.2bn in 2019–20, the report said this could indicate growing non-compliance or earlier underestimates.

HMRC’s “wealthy team” now covers 850,000 individuals and will grow by 400 more staff. 

But MPs said treating all wealthy taxpayers as one group is inadequate, recommending segmentation by wealth and complexity.

They also criticised HMRC’s limited penalties for tax enablers, calling this “particularly disappointing,” and urged stronger enforcement.

High Pay Centre director Luke Hildyard told the Star: “Opponents of a wealth tax argue that it would drive the hyper mobile super rich overseas.

“But in addition to doubts about whether wealthy individuals are actually as willing and able to flee to other jurisdictions, there are also big uncertainties about whether or not we’d miss them. 

“The Sunday Times collects a list of Britain’s richest families and the country’s biggest taxpayers and interestingly there aren’t many people who appear on both lists. 

“Obviously, if people aren’t contributing much tax to begin with, the main consequence of them leaving the country is that we end up with a much fairer and more equal society.”

Tax Justice UK interim director Fariya Mohiuddin said: “If HMRC isn’t able to tax the super-rich fairly, how can anyone have faith in a system that has one set of rules for the wealthiest, and another for everyone else? 

“At the heart of this story is the urgent need for HMRC to have the resources and political backing for it to be an effective and efficient tax authority that can administer a tax system that is fair and fit for the 21st century. 

“With millions waiting for healthcare treatment to essentials being unaffordable for many – HMRC needs to be able to collect the right tax from the super-rich. 

“Failing to do so lets money be squirrelled away into tax havens like some of the British Overseas Territories which deprives our communities, hospitals and schools of the cash they need. 

“The government must give HMRC backing by investing in it for the long-term, to make the system fair, and ensure British tax havens implement transparency measures to prevent offshore hoarding of wealth.”

An HMRC spokesperson said the government is “determined to make sure everyone pays the tax they owe.”