A man has been flown to hospital with head injuries after what police believe was an assault on a footbridge over the A12.

The 55-year-old was taken to hospital by the London Air Ambulance last night after police were called by paramedics to the footbridge off Colworth Road in Leytonstone.

The Guardian understands the helicopter landed in McDonald's car park in Gainsborough Road at 6pm before the man was taken to it by ambulance.

A person has been arrested over the incident but police have failed to confirm their age and gender, or what they were arrested on suspicion of.

However, the Met confirmed it is treating the incident as an assault.

A passer-by, who did not wish to be named, noticed the police guarding the bridge, which was closed to the public after the incident.

He said: "There was quite a bit of blood. There was a bloodsoaked towel on the bridge which someone must have used to stem the cut to the man's head.

"There were items scattered about. They made it look like it happened on the floor behind the fence. There were bloody towels there too.

"There were just a couple of PCSOs interviewing members of the public when I got there."

The Guardian has requested a condition update on the man.