The “Tax Gap” difference between the amount of tax that should be collected and the amount actually collected, grew from £30.8 billion in 2020/21 to 35.8bn in 2021/22.
At the same time £1.5 billion went uncollected from wealthy people subject to self-assessment.
Tax Justice UK Head of Advocacy and Policy, Rachael Henry , said: “The tax gap remains large and it’s worrying to see the amount of money uncollected from wealthy people continue to rise.
“At a time when public services are on their knees it’s vital we are collecting all the tax revenue we can. HMRC inspectors are worth their weight in gold and the government needs to give HMRC the resources it needs to collect these outstanding tax revenues.”