He is most noted for his achievements as a bomber pilot with the Royal Air Force (RAF) during the Second World War, and for his reputation as a highly influential figure within Britain's black communities.

He was a mentor to many leading black civil rights activists in Britain, including Trevor Carter, Dorothy Kuya, Cleston Taylor, and Winston Pinder, and was a close personal friend of the president of Guyana, Cheddi Jagan.

These riots resulted in the British government dispatching a royal commission, which included English politician Stafford Cripps, to investigate the causes behind them.

[9] Strachan risked the long and dangerous journey in U-boat-infested waters,[12] spending his time smashing tin cans to provide metal for Britain's war effort against Germany.

[8][11] Struggling to understand British culture, Strachan saluted a porter at a train station in Bristol, believing that he was an admiral because of his work uniform.

[21] He recalled the events of this incident, the stress of which ended his ability to continue his career as a pilot: I asked my engineer to make sure we were on course to get over the top of the cathedral, He replied 'We've just passed it.'

[22] Strachan, now a Flight Lieutenant at the age of 23, was sent to an RAF base in Bedfordshire to investigate racial tensions between Black and white military personnel there.

[23] During this time, he once sat as a member of courts-martial, and in incidents he worked as an advocate on behalf of black servicemen – experiences that his biographer, David Horsley, theorised inspired Strachan's future career in law.

[20] Once, while stationed in Yorkshire near Hull, Strachan visited a dentist in an underground surgery, returning to the surface to find that all the buildings above ground had been destroyed by bombs.

[24] Strachan, his wife Joyce and their children, all briefly moved to Jamaica in 1946, and he resumed the civil service job that he had held prior to the war.

[29] When the Afro-Caribbean communist and civil rights leader Trevor Carter moved to Britain, he began living with the Strachan family and stayed with them for several years.

[25][28] His activism as a CPGB member put him into contact with many influential British communists and socialists including Kay Beauchamp, Palme Dutt, and Cheddi Jagan.

[28] Culturally, Strachhan also came into contact with the works of communist musicians, including Alan Bush, A. L. Lloyd, Ewan MacColl, and with the dramas of Bertolt Brecht.

[28][29] According to the Morning Star newspaper, Strachan told one of his sons: "Because of the way my life was to go if I hadn’t discovered Marxism I would have undoubtedly ended up in a mental institution.

[10][28][37] The CLC sought to create an alliance of left-wing nationalists and communists across the British Empire, and was associated with the World Federation of Trade Unions.

[40] Under Strachan's leadership, the London branch of the CLC held regular educational classes for its members, reading books such as Eric William's Negro in the Caribbean, Cheddi Jagan's Forbidden Freedom, Harold Moody's Negro Victory, Andrew Rothstein's A People Reborn, Learie Constantine's Colour Bar, and Richard Hart's Origin and development of the People of Jamaica.

[41] During a 1951 meeting in Lambeth Town Hall, Brixton, hosted by Labour Party MP Marcus Lipton, Strachan expressed his anger at the British government's attempts to scapegoat black immigrants for their failure to solve the post-war housing crisis.

[35] With the 1948 arrival of the HMT Empire Windrush to Britain transporting hundreds of West Indians, Strachan and the London branch of the Caribbean Labour Congress established a committee to help them and arranged a welcoming event at Holborn Hall in July of that same year.

[30] In 1952, reactionary conservative leaders in the Caribbean, led by Grantley Adams of Barbados, turned on their left-wing and anti-colonial allies, persecuting all whom they believed to be communists.

[10][25] He had wanted to study law earlier but could not afford to do so, due to the combined weight of his family commitments, his political work, and his fulltime employment, first as a cost-accountant in Kilburn for a baker's and confectioners, then later as a clerical assistant for Middlesex County Council.

[28] In 1971, Strachan was elected president of the Inner London Justices Clerks Society,[25] before becoming involved in Lord Avebury's investigation into the death of Walter Rodney, a political leader in Guyana.

[33] Strachan then became a founding member of Caribbean Labour Solidarity (CLS), an organisation formed in London by his friends Richard Hart and Cleston Taylor in 1974.

[28] During one trip to Guyana in 1996 as a guest of the Jagans, Strachan began to feel ill and upon his return to Britain it was discovered that he was suffering from motor neuron disease.

[28] A memorial meeting for Strachan was held on 5 July 1998, attracting a large number of influential political leaders and activists including Trevor Carter, Richard Hart, John La Rose, Cleston Taylor, Phil Sealey, Clem Derrick, Ranjana Sidhanti Ash, Norma Gibbs, and Raymond Kudrath.

[52] Strachan's biographer, David Horsley, characterises him as a "civil rights pioneer", and a "remarkable and often overlooked figure in British Caribbean history".

[10] Communist activist Bob Newland, a member of the London Recruits who travelled to apartheid South Africa to support the African National Congress, called Strachan his mentor.

[53] While Strachan has been recognised and celebrated by many of the above, some researchers note that many key texts and sources on black history in Britain made no mention of him, even when the authors were likely to have known him personally.

[33] Peter Frost, a researcher of British leftist history, wrote in the Morning Star that he believed Strachan's communist beliefs were somewhat responsible for the movie not being created.

[36] Though not making an appearance in the story, Andrea Levy's novel Small Island (2004) contained two main characters which were inspired by Billy Strachan's life.

[62] One display in the museum's Second World War galleries created by History Professor Richard Overy featured objects relating to Strachan.