After gaining access to offshore accounts of the UK’s largest banks over the last 12 months, HM Revenue & Customs will offer account holders who have not paid their tax bill the opportunity to pay up, Accountancy Age understands, although HMRC will not bill the offer as an amnesty.

HMRC, which expects to rake in over £1.75bn, will grade the charges according to its new penalty regime, which includes the possibility of suspended penalties.

Industry insiders suggested the most likely penalty would be 10% for those who had turned a blind eye to their offshore liabilities. It is thought unlikely that any amnesty would apply to criminal assets.

Grant Thornton senior partner Mike Warburton said Ireland had imposed a charge of 10% with its tax amnesty. According to new figures from the Irish Revenue, its offshore accounts investigation has scooped 856.2m euros (£578m).

While Warburton expected HMRC to recoup more than its estimate, he thought committed tax evaders had moved their funds to jurisdictions out of HMRC’s reach.

An amnesty would also strongly suggest that HMRC was unable to process the huge amount of data made available by the banks.

HMRC refused to comment.