The tax yield from the Let Property Campaign, which launched in 2013, dropped almost 50% from around £34m in 2019-20 to around £17m in 2020-21, with the numbers of those disclosing falling from 7,578 to 4,330.

This was the lowest figure recorded in seven years, according to figures obtained under the Freedom of Information (FOI) request by accountancy firm Saffery Champness.

The figures released by the tax authority also showed the number of penalty notices HMRC issued to buy-to-let landlords. In 2019-20 HMRC issued 8,116 penalty notices worth out £5.5m and in 2020-21 this dropped to 4,297 notices worth £2.3m.

In the tax year 2019-20 HMRC issued 408 notices for landlords who were considered to have not taken reasonable care and in in 2021 the number of notices dropped to 364. There were 5,578 notices for those who failed to notify HMRC in 2019-20 and only 3,348 in 2021 and there were 134 notices issued for those who deliberately misled HMRC, this figure dropped to 58 in 2020-21.