A man is fighting for his life after he was knocked unconscious when he tried to intervene in a city centre brawl.

The victim, who is in his 50s, was punched in the face whenabout 15 people fought in Manchester in the early hours of Saturday morning.

He was taken to hospital with a serious head injury and remains in a critical condition. A second man in his 20s was taken to hospital after suffering cuts and bruises, Greater Manchester police said.

A 25-year-old man arrested near the scene on suspicion of affray and a 32-year-old woman arrested on suspicion of assisting an offender have been released while under investigation.

Detectives are trawling CCTV footage for evidence and seeking to speak to witnesses to the fight, which took place outside The Printworks entertainment complex.