Crackdown on tax avoidance brings in an extra £1bn HMRC has clawed back an extra £1bn over the last year in an unprecedented crackdown on payment loopholes. A new report says tax authorities have managed to close down a raft of tax avoidance schemes used to lighten the tax burden. In the year ending March 31, investigations had yielded £2.7bn in tax, up from £1.8bn the previous year.