Police are appealing for witnesses after a man was struck over the head in an attack in The Lanes, Brighton.
Shortly after midnight on 21 November a 30-year-old man was walking in Meeting House Lane when he was attacked from behind.
The attacker ran off after a member of the public heard the assault and shouted.
The victim, from Hove, suffered a suspected fractured skull, cuts to his head and ear that needed stitches and bruising to his face.
Officers are speaking to businesses and residents in the area and trawling through CCTV footage recorded in The Lanes to try to identify the attacker.
Detective Constable Aaron Halsey said:
This was a particularly violent attack and as a result the victim has sustained serious injuries.
It is very important that we speak to anyone saw or heard any part of what happened and I would appeal to anyone who knows anything at all to contact us.”
A 22-year-old man from Brighton has been arrested and questioned on suspicion of assault. He was released on bail until 21 January.
Anyone with information should email email@example.com quoting serial 4 of 21/11, call 101 or contact the independent charity Crimestoppers anonymously on 0800 555111.