Political dissident Gerard Hoarau, 34, was shot dead on his doorstep in Edgware on 29 November 1985.
He had just left his home on Greencourt Avenue when a gunman fired a Sterling sub-machine from the other side of the road at around 10.15am.
At the time of his death he was president of the Seychellois National Movement, an exiled group opposed to the regime of France-Albert Rene, who came to power following a coup on 5 July 1977.
No-one was charged the murder as a result of the police investigation, though three people were convicted of perverting the course of justice in 1986.
A review of the investigation began in 2016 and on 2 August 2018 a 77 year-old man was arrested in Antrim, Northern Ireland, on suspicion of conspiracy to murder before being released under investigation.
This man, a former private detective named as Ian Withers, told the BBC he had been left in “legal limbo”. He denied any knowledge of the murder.
On 9 August 2018 a man in his 80s was arrested on suspicion of conspiracy to murder on arrival at Gatwick Airport before being released on police bail.
In November 2021 the Gerard Hoarau Foundation was launched to mark the 36th anniversary of the assassination and pay tribute to his attempts to bring democracy to Seychelles.
Contact Crimestoppers anonymously with information on 0800 555 111.