An Essex engineer who became a Nazi spy was condemned to death at the Old Bailey.

HE was, or seemed, a nondescript man without ambition, lacking any sort of attitude or opinion. Born in Barking, he moved east to Essex, settling in Thundersley after the war. That move appeared to be the most dramatic thing that Walter Purdy had ever done with his life. He did some sort of job with a firm that made water softeners, then towards the end of his life worked as a storekeeper for Ford in Dagenham. He died in Southend Hospital on July 26 1982. And that was the end of this particular version of Solomon Grundy.

Yet the apparently ordinary Englishman hid a sensational personal secret that was to become the stuff of legend. He had been tried, and come within an inch of being hanged, for High Treason. Through the war years he willingly, even eagerly spied against Britain on behalf of his beloved Nazi Germany. In semi-fictionalised form, he was to enter TV legend as a character so unlikely that many viewers of the TV series Colditz assumed he was invented for dramatic effect. Yet he was real. Walter Purdy of Thundersley was the Colditz traitor. Colditz Castle, the supposedly "escape-proof" medieval castle near Leipzig, was the place where prisoners-of-war with a record for escape attempts from more leaky camps were sent, in an attempt finally to shut the door on them for good. As we know from films and TV, Colditz famous proved to be not so escape-proof after all.The castle was a swarming hive of busy and ingenious escape-artists, plotting, hacking, building, forging, disrupting, all with the aim of getting out of Colditz, back to Britain and on with the fight. And even if they couldn't escape, at least they could disrupt the Grman war effort by causing maximum chaos and tying down as much enemy manpower as possible. Colditz, if you were British, was a very single-minded community. Yet one inmate was secretly working directly counter to this effort. He went by the name of Bob Poynter. He was as English as any prisoner in Colditz, but he was working for the Nazis. Bob Poynter was the assumed name taken by Walter Purdy.

Purdy's extraordinary path to becoming the Colditz traitor started somewhere back in his adolescence. Only the bare facts are known, but it is possible to second guess the process. He was born in Barking to a dockland family on May 17 1918. It would be hard to imagine a more dyed-in-the wool, working class, London background, and like so many others in that generation, Purdy joined the British Union of Faschists. He was 16-year-old when he signed up at the Ilford branch, provocatively placed at the heart of one of the country's largest Jewish communities. Thousands of other teenagers also briefly adopted the blackshirt uniform of the BUF. But by the outbreak of war in 1939 almost all of them had abandoned this short-lived attempt to create a British version of the Nazi party. In Purdy's case, unusually, some sort of virus appears to have stuck. It is likely that, during this period, Purdy encountered another blackshirt, a figure who was to influence him deeply. This charismatic individual, William Joyce, was destined to become the most notorious traitor of World War Two. Away from the streets of London, Purdy began to build a successful career for himself as a ship's engineer in the merchant navy. Soon after the outbreak of war, he joined an armed boarding vessel, HMS Van Dyck. He was now serving as a merchant navy officer under Royal Navy orders, with the rank of sub-lieutenant. Purdy's war didn't last long. On June 8, Van Dyck was bombed and sunk off the Norwegian coast. After 36 hours in a lifeboat, Purdy was captured and became a prisoner-of-war. And so began the mysterious process by which a British serving officer pledged to King & Country, was transformed into a German spy.

Purdy ended up at the naval internment camp, Marlag, in northern Germany. The head of security at the camp, Onderfuhrer Gussveld, took an interest in identifying POWs who might be sympathetic to the German cause. Purdy caught his eye when he noticed a book that the naval lieutenant was reading. It was a tract about the increasing decadence of the British Empire, called Twilight Over England. Its author - William Joyce, the man Purdy had rubbed shoulders with, back in Ilford. The first stage of turning Walter Purdy began with something as inoffensive as a book-signing. Gussveld offered to send the book to the author for his signature. Purdy willingly complied. Joyce was his hero. William Joyce was now known around the supposedly collapsing British empire as Lord Haw Haw, broadcaster of propaganda designed to sap the morale of the British people - a pesky race who were showing a surprisingly powerful fighting spirit for a country that was supposed to be in terminal decline. In 1943, Walter Purdy joined Lord Haw Haw's radio unit in Berlin. Starting in August, he began to make anti-British broadcasts of his own. In a brazen act of identity theft that puts other recent cases to shame, he assumed the name Bob Poynter, stolen from a fellow POW naval officer he had encountered in camp. He was also integrating into German society. He was billeted with a German couple, and while there he met a pastry cook named Margaret Weitemeier. The pair were soon living together as man and wife. In April 1945, Margaret bore him a son, Stephen.

On March 8 1944, a naval lieutenant named Bob Poynter arrived as a POW at Colditz Castle. Soon after his arrival, German guards discovered the whereabouts of a hide, a wireless set, and an escape tunnel. POWs began to suspect the unthinkable, a British traitor in their midst. Already suspicion was falling on Poynter. Some prisoners remembered him from previous camps as Walter Purdy. One prisoner believed that he ahd seen Purdy salute the Nazi swastika.

Eventually Purdy was summoned before the camp security committee. Their cross-examination skills soon wrung a confession out of the man from Essex. He confessed that he had been a "rat and a traitor." According to one witness, Brigadier Grismond Davies-Scourfield, the decision was taken to hang Purdy within Colditz. In the end, however, nobody could be found to volunteer for the grisly task of execution. Instead, the Germans were told to remove him from the camp, because his safety could not be guaranteed. The Colditz commandant took the threat seriously, removing Purdy to a cell outside the main prison area. In June, he returned to hs old life in Berlin as propaganda broadcaster, interpreter and live-in lover.

At the end of the war, Purdy was picked up by American forces and returned to England. For a while he remained at liberty, and was even awarded a disability pension based on wartime hardships. Purdy now shifted from the shadowland of treachery to a seamy London netherworld. Conveniently forgetting his German missus and son, he started an affair with a Mrs Betty Blaney. If ever a relationship ended in tears, this one did. Discovering about his past, his new squeeze began to blackmail him. Blaney ended in the dock at the Old Bailey charged with extortion.

All this time, Scotland Yard had been preparing a case against Walter Purdy/Boby Poynter. In December 18 he faced the Attorney General, Sir Hartley Shawcross, on a charge of High Treason. Those testifying against him included Margaret Weinemeiier, his wartime German "wife." It took the jury a mere 17 minutes to bring in a verdict of guilty. The judge donned his black cap and Purdy was sentenced to death.

In Colditz, nobody had felt up to the task of operating a gallows. In England, the professionals began to prepare for the task. The executioner Albert Pierrepoint was summoned to Wandsworth jail, where Purdy now resided. The execution date was fixed for February 8 1946. On February 6, just two days before that date, the Home Secretary commuted Purdy's death sentence. Purdy's hero William Joyce was less fortunate. He was hung on January 3 1946.

Purdy was released from jail in November 1954, under Home Secretary's licence, although a departmental memo described him as "the greatest rogue unhung." He married twice, his first wife dying soon after their wedding. His second wife bore him a son. She remained in ignorance of his past until after his death. Purdy told her that he spent his wartime in submarines - an appropriate lie for a man who sought to submerge his past identity. Eventually, the full Purdy story as told above was unearthed by a dogged researcher named Joe West, a helicopter pilot and TV producer. Joe tracked Purdy to his lair in Thundersley, but by then then the Reaper had claimed the old traitor. For 36 years he had successfully eluded his history, hiding it under a mask of anonymity. In the end, Walter Purdy proved far more competent at being a nobody than a traitor.

The file remains open on Walter Purdy. Do any readers have any recollection of his Thundersley days? Please contact Memories via, or ring 01268 469470.