When he reached Manning’s service record he found it was littered with enough basic errors and operational missteps to convince Knox he should never have been allowed in the field, let alone made acting director general. But there was nothing in it to suggest malice was hiding beneath his incompetence. At least, not until Knox found one very odd and very deeply buried operation.

On 7 March 1947, Yevgeny Kuznetsov walked into a small, backstreet restaurant in Singapore. It was midday, and Paul Fenwick, a low-ranking member of Singapore’s British Military Administration, was eating his lunch. Kuznetsov approached Fenwick’s table, sat down opposite him.

‘You are British,’ the Russian said. ‘I am MGB, and I want to defect.’

Singapore in 1947 was, to put it kindly, a mess. The British Military Administration was still restoring most of the colony’s infrastructure after the Japanese occupation of the island during the war. Food was scarce, crime was rampant, and Chinese communist seditionists were stoking anti-colonial protests. In other words, the Military Administration was stretched thinly enough without worrying about a Russian walk-in. But Kuznetsov made Fenwick a tantalising offer.

‘Get me back to civilisation, and I’ll give you the names of all the Russian agents in your country.’

The Administration made a blanket request for assistance to Military Intelligence, MI6, and MI5. All three could have claimed jurisdiction over Singapore. But it was Manning, then working in MI5’s counter-intelligence division, who quickly drafted a memo making the case that as Singapore was a colony, all intelligence operations there fell under MI5’s purview. He also said that, given Kuznetsov’s suggestion about Soviet infiltration, this matter was too serious to be handled by the MI5 security liaison officer assigned to Singapore and someone from counter-intelligence should fly out to interrogate him—and that he was happy to volunteer.

Neither MI6 nor Military Intelligence were inclined to put up a fight, and Manning was on a plane to Singapore the next morning.

It was clear from Manning’s record that this was the moment he became tipped for bigger things. Everyone was impressed with how he handled the mission, and his conclusion after meeting Kuznetsov that every piece of information he’d offered up was entirely fictitious. The report’s coda stated that two days after meeting Manning Kuznetsov’s body was found on the edge of Singapore’s north coast, washed up from the Johore Strait—the price, it seemed, of his failure to trick the British.

This conclusion made sense to Manning’s superiors, but not to Knox.