He served as an electrician with a nightfighter squadron at West Malling, and was then posted to the Rhodesian Air Training Group in Salisbury, Rhodesia (now Harare, Zimbabwe) in 1943.
Then a Detective Sergeant with the Flying Squad, Slipper was one of six police officers chosen by its head, Tommy Butler, to form a special unit to catch the robbers.
According to the police investigation, several of the robbers had left fingerprints or palm prints at the gang's temporary hideout at Leatherslade Farm in Buckinghamshire.
Biggs travelled via Paris to Spain and then Melbourne, Australia, where, despite plastic surgery to alter his appearance, he was identified by his dental records after visiting a dentist.
Slipper travelled to Brazil, where he attempted to arrest Biggs in a hotel in Rio de Janeiro, with the words "Long time no see, Ronnie."
Famously, Slipper was photographed on the plane home, sleeping next to an empty seat, and was christened "Slip-up of the Yard" by the press.
An extradition request was made, but it was denied due to the lack of a treaty between the United Kingdom and Barbados; he was returned to Brazil.
He was involved in several major investigations such as the Bank of America robbery in April 1975, in which £8 million was stolen from a branch in Davies Street, Mayfair.
He sued the BBC for libel after a television film, The Great Paper Chase, portrayed Slipper (played by Jeremy Kemp) and his colleagues as incompetent.
The legal action was financed by Sir James Goldsmith, Slipper won damages of £50,000, his costs (estimated at £400,000), and an apology.