A 26-year-old workman was seriously injured after being struck in the face by a manhole cover as he carried out building work at a primary school.

People near the scene said the victim, who has not been named, was down a manhole when a cover on chains came loose and hit him on the head.

It is understood to have seriously injured his head and damaged his stomach.

He was flown by air ambulance to hospital in London.

Witnesses said teachers closed the blinds at Langley Green Primary in Stagelands, Crawley, so as not to scare the pupils.

Justine Connolly, 41, of Crawley, said: “I got there as the helicopter landed.

“I was told a young man was down a manhole with a manhole cover on chains hanging near him.

"This broke loose and perforated the young guy's stomach and damaged all his lower face.

"They were there a while before the helicopter flew off with the man.” The West Sussex County Council-run school said no children witnessed the incident.

A Sussex Police spokesman said: “Just after 11am on Friday, a Kent man who was working in a hole on a building site at Langley Green Primary School in Crawley received a head injury believed to have been caused by a falling manhole cover."