HMRC has given British investors in tax havens such as Liechtenstein a chance to come clean in exchange for reduced penalties. But it is now poised to turn up the heat on wealthy tax evaders and their accountants.

Acting HMRC chairman Dave Hartnett told the publication his organisation was determined to crack down on a minority of repeat offenders in the profession who advise clients on using tax havens illegally.

He said that HMRC was building a detailed picture of rogue accountants as part of an investigation into rich investors who have hidden money in Europe and the Channel Islands.

If HMRC finds an accountant is involved in illegal offshore tax activities it will consider investigating all the clients of the accountant in an effort to reduce lost tax revenue.

Last year HMRC raised £400 million ($792 million) after British taxpayers with money in offshore accounts run by high street banks were offered leniency in return for voluntary disclosure.

“We are constantly building up intelligence on firms that help their clients into any sort of found its way to Liechtenstein and we may pursue that enquiry quite vigorously until we understand it.”

HMRC is using powerful software to compile evidence of accountants linked to offshore tax evasion. This could pave the way for prosecutions of accountants if they are shown to be complicit in a client’s offshore affairs, which is classed as fraud.

Mr Hartnett said that HMRC hoped to start its first prosecution of an investor over offshore evasion within months. He added that the 300 British investors with Liechtenstein-based bank accounts ranged from professional investors and writers and featured some “household names”.