The investigations are part of a fresh broadside against tax evaders by the authority, and are focused on 10 people with offshore accounts and six in medical trades. Hundreds of civil cases are expected to follow.

HMRC’s original campaign aimed at those using offshore accounts to evade tax began in 2007 and gathered £400 million ($649 million) from 45,000 disclosures, as well as £91 million in follow-up enquiries. A second campaign launched in 2009 raised £85 million from 5,500 disclosures, and a further £6 million in follow-ups.

New penalties introduced in April raised the maximum fine level for those with offshore accounts to 200 per cent of unpaid tax, plus the original tax owed.

HMRC said offshore tax evaders come from a broad range of professions, including "chip shop owners, taxi drivers and landladies". The tax authority has also threatened to publish the names of people who deliberately evade tax.

"Criminal investigations have not been the weapons of choice for HM Revenue and Customs, but now they are part of the armoury," Gary Ashford, representative for the Chartered Institute of Taxation, told the BBC.

He advised evaders to make a disclosure, as they can reduce the penalties they face by coming forward voluntarily.