Police have launched an investigation after a man was found lying in a Bristol street with serious head injuries early today.

A passer-by discovered the unconscious man in Stanley Street, Totterdown, at 6.30am on Tuesday morning and called the emergency services.

He was taken to Bristol Royal Infirmary by ambulance.

Police are trying to establish how he came to be injured.

Initially it was thought that the man might have been knocked down by a car but now officers believe he was attacked.

A number of streets in Totterdown have been sealed off while officers carry out a search of the area for a weapon that could have been used in the attack.

Officers were also carrying out house to house inquiries.

Anyone who was in the area last night or early today who may have seen something that could help the inquiry is asked to contact police on 0845 4567000.