A total of 617 people faced criminal prosecutions in 2012-13, up from 302 in 2011-12 and well in excess of HMRC’s target of 565 prosecutions for the year, according to figures obtained by law firm Pinsent Masons.

Jason Collins, a partner with the company, said investigators are focusing more on middle class tax evaders than the super-rich.

“There is a definite pick up in investigatory action against white collar businesspeople. HMRC’s policy is clearly to use hard-line sanctions to help deter any wrongdoing.

“These aren’t necessarily individuals who owe hundreds of thousands of pounds, but people like doctors, dentists, lawyers, construction contractors and restaurant owners who have not declared amounts in the tens of thousands.

“Those in a position of trust or responsibility, such as lawyers, medical practitioners or business or financial consultants, are increasingly in HMRC’s line of fire, and we are also seeing an increase in buy-to-let investors falling foul of the system.”