An investigation is under way after the death of a man at the Royal Lancaster Infirmary.
Police were called to the hospital at 5.13pm on Saturday.
A spokesperson for Lancashire Police said they had been called to support prison officers who were already present guarding a prisoner, a man in his 30s, who had become unwell and agitated.
The spokesperson said officers arrived at 5.20pm and supported HM Prisons colleagues in restraining the man, but at 5.27pm the man’s medical condition worsened, and he stopped breathing and became unconscious.
"He was given CPR, but he was sadly pronounced dead a short time later at 6.30pm," said the police spokesperson.
"Our thoughts are with his loved ones. His next of kin have been informed.
"The matter has been referred to the Independent Office for Police Conduct and they will carry out an independent investigation into the role of the police during this incident. We will of course fully cooperate with them.
"Lancashire Constabulary will retain responsibility for investigating the wider circumstances leading to the man’s death.
"We would ask that people do not speculate on the circumstances surrounding this incident until the investigation has been completed."
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