There was, he insisted, a semi-official redemption programme whereby the US government was seeking to get the bonds back but only at arm’s length. It was not long before the police were knocking on Halksworth’s door.Even then the old hand was unfazed. Deliberate mistakes were often made in such bonds as a security device; ask the CIA, he said. But some bonds had so many mistakes on them it looked like a child had printed them, the police said; exactly, he replied, as if that proved his point But the boxes were fakes, the police said Not my responsibility, I just do the documents, he riposted. But the US authorities say the bonds aren’t genuine, the police said. They would say that, countered Halksworth, because the sums involved are so huge the US Treasury nowadays can’t afford to pay up on them, so they say they’re fakes when they’re not.Indeed, he told the UK police that even after the US secret service had hauled him in to say these were counterfeits, he had continued to authenticate them since he thought the Americans were lying because they could not afford to repay the $2.5 trillion debt. With the bonds, they offered a certificate of authentication bearing Halksworth’s signature.

What the eagle-eyed Mountie spotted was that the letter “s” was missing from the word “dollars” on the bond.This was not what those behind the scam had intended. The idea was not to try to cash the bonds: it was to offer them to financial institutions, along with the authentication documents, and the indication that the US government backed the documents with gold, to secure a line of credit. But the attempt to cash them subjected the whole scheme to close scrutiny. “It was a missed opportunity that makes me sick to this day,” he said recently. At the same time, Halksworth’s work as an examiner of historical documents exposed him to a bizarre world of strange and colourful characters, each with their own money-making scheme. They set him an example that he finally found impossible to resist.It was a member of the Royal Canadian Mounted Police who did for respectable Mr Halksworth. Two years ago, two men – a Korean living in Japan and a Canadian – walked into the Imperial Bank of Commerce’s main branch in downtown Toronto and tried to cash $25m (£15m) of US Treasury bonds.

He became involved in approving United States Federal Reserve bonds for Saudi princes, evangelical churches and Native American tribes.They were experiences which exercised two complementary, but equally unhealthy, influences on him. For years he nursed a resentment about his work on the Scotland Yard fingerprinting system; he was central to it, he complained, and yet the chance to make money on it was taken away from him. He helped issue bonds for the Bank of England and commercial banks. According to the “back of the envelope” list, Theresa May would be offered the position of Culture Secretary, while Caroline Spelman could become Trade and Industry Secretary. Crucially, both Michael Portillo and Kenneth Clarke would be asked to make public statements supporting the new leader and in effect uniting the party for the first time since 1997. Neither is likely to want a job in the new Shadow Cabinet.The “coronation deal”, which could be enacted soon after Mr Duncan Smith resigned, would remove the need for a lengthy and divisive leadership ballot of MPs and 300,000 party members.If any of Mr Howard’s rivals refused to take part in a deal, the Shadow Chancellor’s allies are warning them that he could humiliate them by gaining the overwhelming support of MPs in a vote.