A murder investigation has been launched after a cyclist died in hospital more than two weeks after being knocked off his bicycle in a violent attack.

Eamonn Anderson, 56, suffered serious head injuries when one of a six-strong group of young men kicked him, causing him to fall off his bike on October 25.

Passers-by called for paramedics as the group of men left the scene at around 11.30pm in Oxford's High Street, Thames Valley Police said.

Mr Anderson was taken to John Radcliffe Hospital after the attack, but died on Friday evening. His next of kin have been informed and a post-mortem will take place on Saturday.

Detective Chief Inspector Mike Lynch, of Thames Valley Police's major crime unit, said: "This was a violent attack, which initially left the victim with serious head injuries, and has now tragically led to his death.

"We believe this to have been an isolated incident, and since it occurred, we have been in the process of conducting a thorough investigation into it in order to establish the circumstances and also to arrest those responsible."