HMRC has collected more than £4bn through accelerated payment notices (APNs).
More than 75,000 notices have been issued to people under enquiry for using alleged tax avoidance schemes since they were introduced in 2014. HMRC has issued notices on all the schemes that were already under investigation at that stage.
The average bill for large companies is £6m, while for individuals and small corporates it is £74,000.