A man has been freed by police at a hotel in Milton Keynes after he was taken hostage in east London.
The victim had been taken from the Limehouse area on Thursday by a group of up to four men.
Police said he was taken to a hotel in Milton Keynes, Buckinghamshire, but freed after an ordeal lasting 16 hours by a special police unit.
Four men have been arrested on suspicion of kidnap, false imprisonment and blackmail.
The victim was taken to hospital with facial injuries.
The operation involved the Metropolitan Police, Hertfordshire Police and Thames Valley Police.
Det Insp Alan Pughsley, from the Kidnap Unit, said: "This was a very successful joint operation between the MPS, Thames Valley and Hertfordshire Police in which a man, whose life we believed was in danger, was rescued."