Harold Holt loved the ocean, and enjoyed being portrayed as an active and adventurous prime minister. He was even dubbed 'Holt 007', with a comedy album of the same name recorded by Bob King Crawford. Holt was once photographed in the press in his scuba mask surrounded by three women in bikinis in a James Bond-style pose.

This silent, unedited broadcast footage from the Nine Network shows Holt and his wife Zara spearfishing around the beaches off Portsea on the Mornington Peninsula in Victoria. As is evident from this footage, Zara was also a keen diver and the two would spend as much time as they could at their holiday home and enjoying the natural beauty of the area.

Radio and television carried news of Harold Holt’s disappearance on 17 December 1967. This clip is from the documentaryThe Harold Holt Mystery (Ten Network, 1985).

Outside broadcast technology brought grainy black-and-white television pictures live from Cheviot Beach. It was an almost surreal scene, with helicopters, navy divers and the army arriving to search for Harold Holt. It was like nothing Australia had seen before.

'I know this beach like the back of my hand', Holt said before venturing out into the the turbulent conditions. It was later concluded that high winds, rough seas and rip tides overcame him. It was speculated in the press that his body was never recovered because it was attacked by marine life, carried out to sea by tides or wedged in a rock crevice.

Zara Holt arrives at Cheviot Beach, the location where her husband had entered the rough sea and disappeared. Holt’s Press Secretary, Tony Eggleton, assists her through the media scrum. Zara meets some of the key people who are coordinating the search. She appears remarkably composed.

This is unedited, silent broadcast footage from the Nine Network.

On 22 December 1967, only five days after his disappearance, a hastily arranged memorial service for Prime Minister Harold Holt took place at St Paul’s Anglican Cathedral in Melbourne.

Thousands of people attended and flooded the streets around the cathedral. It was a sombre affair for a nation still in shock. 

Former Australian prime ministers, including Sir Robert Menzies, were in attendance and world leaders and royalty travelled to Australia to pay their respects. President Lyndon Johnson, who only the previous year had toured Australia, made the trip. Her Majesty Queen Elizabeth II was represented by Charles, Prince of Wales.

The search for Holt was exhaustive. Diving teams entered the rough waters repeatedly but were unable to find any evidence or clues to his disappearance.

As each day passed hopes dimmed of finding any trace of the prime minister, let alone finding him alive. Holt had disappeared on 17 December, and the search continued through the Christmas period before being called off on 5 January 1968.

The failure to find any trace of a body or clothing led to speculation that he may not have been swimming there in the first place. But in subsequent years other people have drowned along that coastline without their bodies being recovered.

This is silent, unedited broadcast footage from the Nine Network.

This clip from The Harold Holt Mystery (Ten Network, 1985) includes interviews with two eyewitnesses at Cheviot Beach on 17 December 1967, the day that Harold Holt disappeared.

It opens with a re-creation of Marjorie Gillespie and Alan Stewart on the beach. Stewart followed Holt into the surf but didn't swim out very far because of the rough conditions.

Gillespie was staying next door to Holt's holiday home at Portsea on the weekend of his disappearance. Holt invited Gillespie to watch around-the-world sailor Alec Rose pass by on his yacht. The pair then travelled to the beach in Holt's car while three others, including Mrs Gillespie’s daughter and Alan Stewart, followed in a second car. The group headed to Cheviot Beach where, despite the rough sea, Holt decided to have a swim.

Marjorie Gillespie was once considered the most intriguing woman in the country, and was reportedly having an affair with the prime minister. Holt’s wife, Zara, was certainly aware of a number of women in Holt’s life but chose to turn a blind eye. 'He loved women’, she would later say.

Initially, Gillespie’s presence at the scene was not reported by the police. She was rumoured to have been smuggled away from the beach in the boot of a car to shield her from the public and the media. In later years Marjorie Gillespie shunned public life and rarely spoke about the tragedy.

'He loved women', says Dame Zara Bates in this interview from the documentaryThe Harold Holt Mystery (Ten Network, 1985). 

Bates recalls Holt as a man who could easily make woman fall in love with him. Throughout their marriage she had to turn a blind eye to his many affairs. On the day he disappeared, Holt was at the beach with Marjorie Gillespie, with whom he was rumoured to be having an affair.

Zara had three sons to her first husband, Colonel James Fell, two of which were twins. Their marriage broke down soon after the birth of the twins. After they divorced, she married Harold Holt in 1946. He legally adopted her children from the first marriage, giving them his surname. Tom Frame's biography The Life and Death of Harold Holt (2005) reveals that Holt was the twins' biological father.

Is Harold Holt still alive? Did he commit suicide? Was he drunk or drugged? Did he secretly belong to a crime syndicate? Was he a Chinese Communist spy?

With the media and others battling to comprehend how someone could simply disappear, the void was filled with numerous allegations, rumours, insinuations and conspiracy theories.

The 'Chinese spy theory' was suggested by Ronald Titcombe and appeared in Anthony Grey’s book, The Prime Minister Was a Spy (1983). The claim was that Holt had been spying for the Communists for 30 years and was spirited away by scuba divers to a Chinese submarine waiting offshore. The book made headlines around the world and is a theory that many Australians remember, even if they don't take it seriously.

This clip is from the documentary, The Harold Holt Mystery (Ten Network, 1985).

The day before his disappearance Holt was playing tennis with friends in Portsea and a number of them later told police that he seemed to be in pain. Holt's personal physician had examined him only days before his disappearance stating that he was in good health.

One of Holt's friends at Portsea was John Cloke, a leading orthopaedic surgeon from Melbourne. While police never interviewed Cloke, he kept evidence that Holt was suffering from pain, numbness and weakness in his right shoulder and arm from a disc problem in his neck, pressing on a nerve. Holt dulled the pain by taking a morphine and aspirin mixture. Cloke believed this shoulder injury could well have impaired Holt's ability to swim strongly in rough seas.

This clip is from the documentary The Harold Holt Mystery (Ten Network, 1985).

A Cinesound Review newsreel story about the first - and only - federal election fought by Harold Holt when he was prime minister. The election took place on 26 November 1966.

The most contentious issue was Australia’s conscription of young men to fight in the Vietnam War. Opposition leader Arthur Calwell was opposed to conscription and promised to withdraw Australian troops from Vietnam if elected. Holt was committed to increasing troop numbers and had the support of the US administration.

Over six million people cast their votes, making it the biggest turn out in Australia’s history. It was a resounding victory for Holt with a major swing towards the Liberal–Country Party coalition government who won a record majority. Holt’s victory was even greater than any of those of his predecessor, Sir Robert Menzies.

A month after the election defeat, Opposition leader Arthur Calwell retired and was succeeded by Gough Whitlam.

On 20 October 1966, United States President Lyndon B Johnson arrived in Australia for the first ever Presidential visit to Australia. 'They're really here', said Prime Minister Harold Holt in his welcome speech.

It was a tour very much in the context of the Vietnam War. Socially and politically it was a contentious period in Australia and America and both leaders were facing public unrest as protests against the war increased. Johnson was keen to shore up Australian support for the war and as such the tour was a show of mutual support for both Johnson and Holt. Holt, who had repeatedly used the Democratic Party slogan of 'all the way with LBJ', was facing a general election the following month.

The visit is famous in Australia partly because of the protests that took place during several public appearances by Johnson which included throwing paint at, and lying in front of, his car. It was also noted for NSW Premier Robert Askin saying, 'Run the bastards over!' while riding in the Presidential car.

As the official record only the briefest scenes of protest were included in this film and no mention is made in the narration. Even though many scenes of protest were shot by the crew, the image is altogether one more of triumph and celebration. And indeed many lined the streets to show their support for the President. Prime Minister Holt was said to be very pleased with the finished film and it was released in cinemas throughout Australia.

Johnson returned to Australia the following year to attend Harold Holt's memorial service after the prime minister disappeared off the coast of Victoria. This is one of several films made by the various government film units covering visiting heads of state from this period.

The disappearance of our seventeenth Prime Minister at Cheviot Beach sparked countless conspiracy theories and ultimately overshadowed his political accomplishments.

At the height of the Cold War, with the Vietnam War escalating, Holt moved Australia’s focus away from Britain and more towards America – substantially increasing Australia’s involvement in the Vietnam War. His impromptu speech on the White House lawn declaring himself ‘All the way with LBJ’ indicated his support for US President Johnson.

Holt’s prime ministership represented a major social shift from the tradition and conservatism of the Menzies era, to that of the ‘swinging sixties’. One of the hardest working of Australia’s Cabinet ministers, after 32 years as a parliamentarian, Harold Holt reached the prime ministerial office in 1966.

As Immigration Minister in 1949, Holt had taken initial steps towards a non-discriminatory immigration policy in Australia by allowing 800 non-European refugees to stay and permitting Japanese war brides. Following the introduction of a revised Migration Act in 1958, Holt as prime minister further relaxed restrictions that had previously blocked the entry of non-European migrants. The Migration Act 1966 increased access to migrants other than those from Europe, including refugees fleeing Vietnam, and was the beginning of the dismantling of the 'White Australia’ Policy.

In 1966 he brought in Australia’s conversion to decimal currency. The following year, on 27 May 1967, Australians overwhelmingly answered ‘yes’ to removing the discriminatory clause in Australia’s Constitution under which Aboriginal people were not counted in the census, and in changing the Constitution so that the Commonwealth parliament was empowered to legislate for Indigenous people.

Holt also brought Australia into the ‘space race’ with the construction of the Honeysuckle Creek Tracking Station, and the joint US-Australian communications station at North West Cape, Western Australia.

In September 2005, the Victorian State Coroner found that Holt had drowned while swimming. The Coroner had previously been unable to investigate a death where a body was never found. Harold Holt was the third prime minister to die in office after Joe Lyons (1939) and John Curtin (1945).

The items left in Holt’s briefcase are a significant time capsule of his last days as Prime Minister: a pair of socks, theatre tickets, his tax returns and a couple of combs.

Harold Holt (1908–1967) was Prime Minister of Australia from January 1966 to December 1967. Harold Holt’s briefcase is held at the National Archives of Australia in Canberra.

The Prime Ministers' National Treasures is also available for purchase from the NFSA Online Shop.

In this Commonwealth Film Unit production from 1964, Federal Treasurer Harold Holt introduces Steward Devlin's designs for the new decimal coins. The designs are based on Australian fauna – a kangaroo, emu, platypus, lyrebird, echidna, frilled-neck lizard and feathertail glider (possum). 

Australia had been considering a decimal system since 1901 but it was not until 1959 that a federal government committee began to investigate the issue. In June 1963, Holt confidently announced that the new decimal currency would be called the ‘royal’. Public outrage followed and by September he was telling Parliament that the 'royal' was now the 'dollar'.

A government campaign hit radio and television to educate Australians and prepare them for the changeover to decimal currency on 14 February 1966, by which time Holt was prime minister.

Tony Eggleton was Prime Minister Harold Holt's Press Secretary and close adviser. He was called upon to explain Holt's disappearance during nationally televised press conferences.

This clip is from the documentary, The Harold Holt Mystery (Ten Network, 1985).

This aerial footage of the Mornington Peninsula, at the mouth of Port Phillip Bay from Portsea to Sorrento, illustrates what a wild piece of coastline it is. The bay side is relatively gentle and protected but Cheviot Beach, where Holt disappeared, is on the ocean side and exposed to the elements. Crashing waves break onto reefs and rocky outcrops. 

This is silent, unedited broadcast footage from the Nine Network.

In this Nine News footage from 1967, Opposition Leader Gough Whitlam extends his condolences to Harold Holt's wife and family.

Whitlam was elected leader of the Australian Labor Party following the landslide 1966 victory by the Harold Holt-led Coalition which precipitated Labor leader Arthur Calwell's retirement from politics. Holt's successor, William McMahon, led the Coalition to the 1972 Federal election where they were defeated by Whitlam's Labor Party after 23 years of unbroken Coalition rule.

In this Nine News footage from 18 December 1967, journalists interview Deputy Prime Minister John McEwen and then Treasurer William McMahon as they arrive at Parliament House.

Even before Holt disappeared, there was tension between McEwen and McMahon over economic policies. With Holt missing, McEwen was commissioned as prime minister until the governing parties appointed a replacement. He held the position for three weeks, from 19 December 1967 until 10 January 1968, when the Liberals elected John Gorton as their new leader. McEwen had threatened the Country Party would quit the Coalition if McMahon became the Liberal leader.

Gorton survived a challenge from McMahon and other contenders in 1969 but effectively handed the leadership to McMahon in 1971 after a vote of no-confidence. McEwen left parliament five weeks before McMahon replaced Gorton as prime minister.

This unedited, silent broadcast footage from the Nine Network shows Marjorie Gillespie walking up from the beach.

Rumoured at the time to be Holt’s lover, Gillespie was one of the last people to see him alive.

She was at Cheviot Beach when Holt disappeared from view under the waves. Gillespie’s presence at the scene of the tragedy was not initially reported by the police.