During a month of interrogations, the three gradually managed to convince their captors that they were not trusted by the British and were keen to work for the Japanese. The price of any slip-ups was made clear every morning when, through the bars of their cell, they watched Japanese officers practise their "head-chopping drill".
Back at base, it was clear that something had gone wrong, and when the Oatmeal team suddenly got back in contact without transmitting the security check "MY BOOTS ARE GREEN", it was obvious that the men had been captured.
In fact, Ibrahim had been captured complete with his codebook, detailing such security procedures. But he managed to convince the Japanese that this printed material was a ruse to deceive potential captors and that he had memorised the genuine security checks.
By mid-November the Oatmeal team was being used to "double cross" Force 136, with the Japanese keen to lure other spies into their snare. In Ceylon, meanwhile, SOE was aware that they now had a perfect conduit for feeding the Japanese misinformation.
This triple-cross was masterminded from India by a group of intelligence officers that included Col Peter Fleming, brother of the Bond author Ian. To gain time, they first demanded that the Oatmeal team travel to Penang, 300 miles away through jungle, in order to "investigate U-boat activity".
By this time Ibrahim and his men had been transferred from their cell to a room in the secret police headquarters. Such was their status among the Japanese that they were once, Ibrahim reported, invited to a dinner party at the house of the OC.
Having "crossed" the jungle (in fact the Japanese flew their prize intelligence assets to Penang), the three men bolstered their credentials with their captors by requesting that a "contact" be parachuted in to assist them. Naturally, no new spy could be dropped into the hands of the Japanese, so this contact was "taken ill" just before departure and, in August 1945, supplies were sent instead. "The Japs could not believe that their dream of fooling the British would come true and were quietly congratulating each other," Ibrahim noted.
So delighted was one Japanese officer that, as he watched the supply drop drift to earth, he failed to notice a 10ft deep pigtrap near the drop zone and fell in. "Luckily for him there were no bamboo spikes," Ibrahim recorded.
In fact it was the Japanese who were being fooled. Not only was the shipment missing all its vital components (due to a "packing error"), but the Oatmeal team had quietly been feeding their captors information that the land assault on Malaya would occur on the Isthmus of Kra, 650 miles to the north of where the invasion forces of Operation Zipper were due to come ashore.
In the event, Oatmeal received a message on August 17, before Operation Zipper was put into action, confirming Japan's unconditional surrender following the dropping of the atom bombs on Hiroshima and Nagasaki.
Ibrahim was immediately concerned that "the Japs might just bump us off", and had regretfully to inform his captors that his religion would not permit him to commit hara-kiri with them. Eventually the Oatmeal members were released and made contact with British forces which had landed without opposition in early September.
"It really was incredible," Ibrahim noted in his mission report, "the way the Japs, from private up to general, swallowed everything we told them. But we had to revise our story every night. It was a terrible strain on our nerves."
Ibrahim Ismail was born on October 19 1922 in Johor, a state now in southern Malaysia. After attending the Dehra Dun military academy he was commissioned into the Indian Army following the Japanese invasion of Malaya. From there he was recruited into Force 136, which was to prove something of a nursery for future Malaysian leaders. Others there included Captain Abdul Razak Hussein (later Malaysia's second prime minister); Captain Hussein Onn (its third prime minister); and Mohamad Ghazali Shafie (a future foreign minister).
Postwar, Ibrahim joined Johor's local army before serving with the Royal Malay Regiment (RMR) from 1951. He rose to the rank of battalion commander with 6 RMR and drew on his experience with SOE to help combat his country's communist insurgency. He also served during the Confrontation with Indonesia following Malaysian independence.
In the wake of Sino-Malay race riots in Kuala Lumpur in May 1969, parliament was suspended and Ibrahim joined the National Operations Council, which governed until the restoration of parliamentary rule in 1971. By that time he had been appointed Chief of the Defence Forces, a position he held until 1977, when he retired in the rank of full general. It had not been a relaxing run-up to retirement, as the region was engulfed in the fallout from the Vietnam War and the threat of communist insurgency. Ibrahim had also had to help organise Malaysia's strategy towards Vietnamese refugees.
In 2000 Ibrahim Ismail was appointed a Grand Commander of the Order of the Crown of Malaysia, which conferred on him the honorific title "Tun".
With his wife, Toh Puan Zakiah Ahmad, he had four children. The Telegraph
