A police appeal has been issued to trace Lerone Michael Boye, 27, who escaped from the John Howard Centre in Homerton, east London, at 2pm on Wednesday.
He was sentenced in December last year to 28 years for the murder of 17-year-old Kelvin Chibueze in Ilford in August 2011.
Boye is described as approximately 5ft 10ins tall with a slim build and short black hair. He has a horseshoe-shaped scar on his right cheek and a goatee beard.
He was last seen wearing grey jogging bottoms and a grey or blue sweatshirt with a grey vest over the top and is known to have links to the Ilford area.
The public is advised not to approach Boye but call 999 if they see him.
Anyone with any information about Boye’s whereabouts can also call police on 101 or Crimestoppers anonymously on 0800 555 111.