Erskine was born in 1962 in Hammersmith, the son of an English mother and an Antiguan father, was removed from school young, and had been in institutions and sleeping rough from his teens. He had a long record of burglary.
Between April and July 1987 he entered the homes of elderly people, mostly in sheltered housing and council flats in Stockwell, Clapham and Islington, and strangled them. Seven died: Eileen Emms, seventy-eight; Janet Cockett, sixty-seven; Valentine Gleim, eighty-four; Zbigniew Strabawa, ninety-four; William Carmen, eighty-four; William Downes, seventy-four; and Florence Tisdall, eighty. Several were sexually assaulted. The press called the case the Stockwell Strangler and there was serious fear in sheltered housing across south London that summer.
A palm print left at one scene was matched to him and he was arrested on July 28, 1987 while signing on at a benefit office. He was convicted at the Old Bailey in January 1988 of seven murders and given life with a recommended minimum of forty years, which was then among the longest tariffs handed down in England.
He was diagnosed with schizophrenia and has been detained at Broadmoor. In 2009 the Court of Appeal quashed the murder convictions and substituted manslaughter on the ground of diminished responsibility, holding that the psychiatric evidence available in 1988 had not been properly before the jury; the effect was on the classification, not on his continued detention.
He is also recorded as having intervened in 1996 to stop an attack on the Yorkshire Ripper, Peter Sutcliffe, in Broadmoor. The seven convictions are firm; the higher figure reflects further unsolved deaths of elderly people in London that summer which were never charged.