The police watchdog is investigating after a man in custody fell seriously ill.
The 24-year-old was arrested by British Transport Police at Northwick Park Tube station in north-west London on Wednesday on suspicion of possessing a Class B drug and an offensive weapon. He was taken to Wembley Park police station but became ill and was taken to hospital. The illness has not been specified.
Commissioner Sarah Green, from the Independent Police Complaints Commission, said: "We have met with members of the man's family ... and we will seek answers to the important questions they no doubt have."