The government's spending regulator says wealthy people in the UK can avoid more than they thought, after a sharp drop in the number of fines to super-rich.

The National Audit Office (NAO) said ministers urged ministers to redouble their efforts to ensure that the wealthy owed more money to the Ministry of Finance.

It said the HMRC significantly increased the additional tax revenue collected from the rich by addressing violations, but additional steps are needed to ensure that the rich pay a fair share.

When Prime Minister Rachel Reeves faces renewed pressure to find additional money for public services and the Department of Defense, it is due to warnings that she may be forced to raise taxes in the fall budget.

Nick Williams, the top 10 senior economic adviser, left the position last month, said Thursday that Reeves' spending plan was "uncredible" and needed a reassessment. “The most important thing is that taxes must rise,” he wrote in the Times.

Labor faces calls from unions and left-wing MPs to target wealthy people with tax rates, as the prime minister prepares for next month's spending review due to strict restrictions on public finances.

According to a report by NAO, billions of pounds of additional income can be collected from the rich. It said the annual “compliance gains” of wealthy taxpayers – pursuing non-payment income HMRC collection – more than doubled from £2.2 billion in fiscal 2019-20 to £5.2 billion in 2023-24.

However, it said the rise is more than £1 billion higher than the HMRC's estimated "rich tax gap" and said it "increases the possibility of a large non-compliance among the wealthy population than previously thought".

HMRC calculates the tax gap for the rich - an estimate of the difference between how much they owe and how much they charge - for the fiscal year ending March 2023 of £1.9 billion.

NAO highlighted the scope of further repression, saying that super-rich people have faced much less fines in recent years.

The HMRC issued a fine of £456 to wealthy taxpayers in the fiscal year ending March 2024, down more than 75% from 2,153 fines in 2018-19 to a total of £16.2 million.

Labor announced many tax increases for wealthier individuals in the fall budget, including replacing non-tax systems, increasing capital gains taxes and VAT on private school fees.

Critics about the free market right believe the changes have sparked a large group of people in the UK, but those from the Labor left say the government can go further than target the poorest welfare cuts in society.

According to the NAO report, the HMRC-supervised population of wealthy people increased from 700,000 in 2019-20 to 850,000 in 2023-24.

The rich, defined as people who earn more than £200,000 per year or own assets of more than £2 million, paid £119 billion in personal tax in 2023-24, accounting for 25% of the total personal tax revenue.

HMRC has a team of 910 employees focused on compliance for the wealthy, although it dissolved a dedicated department targeting assets above £10 million in 2017. However, the Minister provided additional funding for the tax office in the fall budget, including preparing to address wealthy offshore violations and fraud.

Gareth Davies, head of NAO, said: “HMRC is worth mentioning that the additional tax revenue generated by its compliance work from wealthy taxpayers has increased significantly, but this may indicate that the level of non-compliance is higher than previously estimated.

“HMRC should also seek greater transparency to give public confidence to all taxpayers who contribute their fair share.”

A spokesman for HMRC said: "It is our responsibility to make sure that everyone pays the right taxes in accordance with the law, regardless of wealth or status. The government is offering the most ambitious programme ever to close the tax gap and bring an additional £7.5 billion in public services to public services in 2029-30 to 2029-30."