Escaped prisoner Ian McLean is thought to have fled the UK within hours of walking out of Littlemore Hospital, police believe.

The 44-year-old – given a life sentence in 2004 for a frenzied knife attack on a former lover – was being kept in an unlocked unit at the mental health facility and was last seen by staff at 10pm on Sunday.

Police spokeswoman Hannah Williams said there had been two unconfirmed sightings of McLean in the UK and it was thought he had fled to mainland Europe on Monday.

Thames Valley Police is refusing to say if it believes McLean was smuggled overseas or had travel documents. The force has also refused to say why in its initial alert it did not warn people that he was a serving prisoner with convictions for violence.