20 years behind bars for youngest ever hitman, aged 15

Britain's youngest hitman will spend at least 20 years behind bars for the "ruthless and clinical execution" of a young mother on her doorstep when he was only 15.

Santre Sanchez Gayle was paid £200 for the contract killing of Gulistan Subasi, 26. CCTV cameras recorded him calmly walking to the flat, pulling a sawn-off shotgun from his rucksack and opening fire.

Known as "Riot", the Kensal Green Boys gang member has two relatives serving life for murder. Cousin Donnel Carty killed City lawyer Tom ap Rhys Pryce in a 2006 robbery in Kensal Green. Half-brother Lloywen Carty killed Lee Subaran at Notting Hill Carnival in 2004.

Gayle, now 16, of Willesden, was detained at Her Majesty's pleasure and ordered to serve at least 20 years. The man who recruited him, Izak Billy, 21, of Kensal Green, will spend at least 22 years behind bars. Both were found guilty of the murder, which took place in Hackney on March 21 last year.

Gayle showed no reaction as Judge Stephen Kramer QC said : "It was an efficient, ruthless and clinical execution." Subasi's estranged husband Serdar Ozbek, 28, has been cleared of ordering her killing.