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

He died yesterday afternoon, police confirmed today.

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.

Construction company Balfour Beatty confirmed an employee of one of their subcontractors had died at the school on Friday.

A spokeswoman said: "Our immediate thoughts are with the family and friends of our colleague.

"The Health and Safety Executive and Sussex Police are carrying out a joint investigation with the full co-operation of Balfour Beatty to understand how this tragic incident occurred.

"Therefore, it would be inappropriate to comment further at this time."

A Sussex Police spokesman said: “A man who suffered a serious head injury believed to have been caused by a falling manhole cover, while working in a hole on a building site at Langley Green Primary School in Crawley on Friday has died.

“The man from Kent was taken by air ambulance to the Royal London Hospital in East London but sadly died there on Monday afternoon.

“Police and the Health and Safety Executive (HSE) are working together to investigate the circumstances.”

A HSE spokesman confirmed they were supporting the police investigation.

West Sussex County Council said: "Together with the school we would like to express our sympathy to the family and friends of the man. At this stage it would be inappropriate to comment further as an investigation by the HSE is taking place."

Would you like to pay tribute to the victim?

Email Anna Roberts.