It’s the £30bn industry that has prospered like no other during the recession – but nobody champions its success. Those working in it operate across all sectors, from public to private, with little regard for the consequences of their actions. They might work near you in the office or they might be the bloke you say hello to down the pub. You might be sitting next to one now.

They are Britain’s fraudsters: difficult to detect, almost impossible to put behind bars. But last week the big crackdown that has long been promised by the UK’s authorities began.