AN investigation is to be launched into a woman's death in police custody.

Police from an outside force are to be called in to investigate how the 61-year-old patient at a psychiatric hospital, came to die in a Middlesbrough police station cell, less than two hours after her arrest by Cleveland Police officers.

A post mortem examination, carried out by a Home Office pathologist, established that the pensioner, a patient at St Luke's Hospital, Middlesbrough, died from asphyxia.

A "thorough and impartial" investigation was last night pledged by the Police Complaints Authority, which will supervise the inquiry.

A spokesman for the Tees and North East Yorkshire NHS Trust said: "We can confirm that the person who has sadly died while in police custody was a patient at St Luke's Hospital. "

The spokesman added: "Regardless of the outcome of the inquest, Tees and North East Yorkshire NHS Trust will carry out an internal investigation in line with national guidance.''

Cleveland Police said the name of the woman, who was arrested and died on Wednesday, was being withheld until all relatives had been informed.