Joe Cassano has been invisible for so long – since the 2008 crisis, the former head of AIG’s now-notorious  financial products division has not given a media interview and is only rarely photographed – that it was a revelation to watch his appearance on Capitol Hill.

Mr Cassano’s mystique was such, and the expectations of him so low, that my first impression was that he was a good witness. His co-operative, friendly, somewhat geeky demeanour in front of the Financial Crisis Inquiry Commission was unlike that of a brash master of the universe.

This helped him in his striking assertion that AIGFP, which made multi-billion dollar mark-to-market losses on its portfolio of credit default swaps and turned AIG into the dark heart of the financial crisis, did not make any mistakes in credit risk management.