What happened to Harold Holt? Australia tries again to solve riddle of missing prime minister

In the summer of 1967 in Australia, just before Christmas, Harold Holt, the country's Prime Minister, decided to go for a dip at his favourite beach.

Disregarding the blustery conditions, he waded into the rough surf near Portsea, south of Melbourne, and swam out. Friends on the shore glimpsed him on the crest of a wave and then he vanished, never to be seen again.

Mr Holt's disappearance off Cheviot Beach stunned the nation, and many Australians refused to believe he had drowned. He was, they believed, an experienced swimmer who just before entering the water had boasted he knew that beach "like the back of my hand". A keen snorkeller and spear fisherman, 59-year-old Mr Holt liked to project the image of a blokey prime minister in his element outdoors.

Soon, the conspiracy theories began to fly. Had Mr Holt been assassinated by the CIA because he intended to pull Australian troops out of Vietnam? Had he committed suicide? Had he been spirited away by a Chinese submarine because he was a spy for Beijing? Or had he faked his drowning - as the former British MP John Stonehouse did in 1974 - to join a lover in the south of France?

For Australians, the mystery provided a home-grown version of the President John F Kennedy assassination intrigue. The absence of a body helped to fuel the wilder theories, and the police file was never closed. Now, 36 years on, the investigation into the country's oldest political whodunnit is about to be resurrected.

Graeme Johnstone, the Victoria coroner, announced yesterday that the Holt case would be re-examined as part of an inquiry into more than 100 unsolved deaths in the state. Mr Johnstone may hold an inquest, which means that witnesses would be called and - who knows? - new evidence could be unearthed. An inquest was not possible then without a body, but the law has changed, prompting police to go back over old files.

The announcement sent a frisson through suburban living rooms, reigniting interest in one of the strangest episodes of modern Australian history. Mr Holt was nearly two years into his term of office when he flew from Canberra to Melbourne in a Royal Australian Air Force jet, planning to spend a weekend with friends including Marjorie Gillespie, his secret lover. Those were different times, and there were no security minders with him when he drove his maroon Pontiac Parisienne to his beach house in the fashionable resort of Portsea on the Friday night.

Mr Holt's wife, Zara, stayed in Canberra because the couple were intending to go to Portsea for Christmas. On Saturday, the Conservative leader played tennis and went for a walk. The next morning, after delivering three lobsters to Ms Gillespie's holiday home, he took her to watch the English round-the-world solo sailor, Alec Rose, arrive at Port Phillip Bay. They were accompanied by Gillespie's daughter, Vyner, her medical student boyfriend, Martin Simpson, and Alan Stewart, a house guest of the Gillespies. On the way home, they stopped for a swim. The patrolled beach at Portsea was closed because of poor weather, but Mr Holt was determined to swim at neighbouring Cheviot, infamous for its dangerous surf. Mr Stewart, the only person to join him, stayed in the shallows. Mr Holt mentioned the tide was high and plunging in, still wearing his sneakers. Then he disappeared, apparently sucked out to sea by an undertow. Ms Gillespie said later: "It was like a leaf being taken out. It was so quick and final."

Zara Holt flew to Portsea with Tony Eggleton, her husband's press secretary. A massive air, land and sea search continued for three weeks. Fishermen, marine scientists and even astrologists were consulted. A shark caught near by had its stomach contents inspected. But there was no sign of Mr Holt.

The sea claims dozens of lives every year in Australia, but many people were reluctant to accept that something as mundane as drowning had accounted for Mr Holt. Some suggested Australia's 18th prime minister had committed suicide because he faced a possible leadership challenge. But he had shown no signs of depression and his wife said: "Harold was too selfish for that." In the fevered Cold War climate, conspiracy theories abounded. One of the most outlandish came in a 1983 book by a British author, Anthony Grey, who claimed Mr Holt had been spying for China for 20 years. He had been rumbled by Australia's intelligence services, Mr Grey claimed, so China sent a submarine and two frogmen to whisk him to asylum.

The CIA theory was equally fanciful, given that Mr Holt was famous for pledging to go "all the way with LBJ" during a visit to the White House in 1966. But he did have a colourful private life. In a television documentary in 1985, Ms Gillespie dropped a heavy hint that she had been his mistress. Zara Holt fired back the crushing riposte that Mr Holt had had lovers in Melbourne, Sydney, Canberra and Hong Kong, as well as in Portsea. "She [Gillespie] was one of the queue formed on the right," she said. "It went on all the time."

Nowadays most people believe the conventional version of events: that Mr Holt was swept out to sea and drowned, his body consumed by sea lice that can strip a corpse of flesh in 24 hours. Friends said he was an excellent snorkeller who used to practise holding his breath for up to two minutes during dull spells in parliament. But he was not a particularly powerful swimmer, he was 59 and he had a long-standing shoulder injury. Months earlier, he had to be helped to shore by two friends after his snorkel sprang a leak at Cheviot Beach.

His biographer, Tom Frame, told the Australian Broadcasting Corporation yesterday that police made a full investigation at the time. Legal experts said they doubted fresh evidence would be found. His family, too, are sceptical of any new twist to the story. His son, Sam Holt, a Melbourne lawyer, called the reopening of the case "just a tidy-up operation as far as I'm concerned".

He added: "We've always believed the death was purely accidental. There was nothing sinister about it, and we've never had any doubt about that." He said the inquiry might "put a stop to silly rumours about Chinese submarines".

Laurie Newell, the police inspector who led the search, said: "He wasn't a young man any more. I think he fell for his own publicity. He believed he could not drown."

GREAT DISAPPEARING ACTS

Lord Lucan

Britain's most infamous fugitive, Lord Lucan, right, missing since November 1974, is wanted for the murder of his children's nanny and the attempted murder of his wife. Sightings continue to be reported, but in 1999 the High Court ruled him dead, although his body has not been found.

John Stonehouse

In November 1974, after the collapse of his companies and revelations of an extra-marital affair, John Stonehouse, a Labour MP who had served as postmaster general, faked his apparent drowning. Two years later he was found alive and well and living under an assumed name in Melbourne, Australia, after which he was jailed for fraud.

Agatha Christie

Afterlearning of her husband's affair in December 1926, Agatha Christie's car was found on the edge of a quarry. She waslocated 11 days later hundreds of miles away, calling herself Theresa Neele and suffering from amnesia. Christie, left, never spoke about the incident.

Richey Edwards

Richey Edwards, right, a troubled member of the Manic Street Preachers, was last seen in February 1995, the day before his car was abandoned at Aust Services, a suicide spot. It is believed he may have taken inspiration from the author J D Salinger, who also vanished without warning to escape the pressures of fame.

Reginald Perrin

The fictional television character Reginald Perrin, no longer able to stand life as a jaded sales executive at Sunshine Desserts, faked his suicide, leaving behind his clothes on a Dorset beach. After a stint as a pig farmer, Reggie returned to suburbia in the guise of his non-existent best friend, Martin Wellbourne, to pick up where he left off.