Maggots have been falling from air vents near operating theatres in Barnet Hospital, it was revealed this week by hospital staff.

One worker said that in two weeks, 50 maggots had fallen from the ceiling, but a hospital spokesman said there had been only three.

The maggots, which had apparently been eating dead pigeons, fell onto the floor between two operating theatres on the hospital's third floor.

The staff member, who did not want to be named, said maggots had started landing in the anaesthetic room and between operating theatres around seven months ago.

They first appeared after flies laid eggs on pigeons' carcasses which had nested in the hospital roof, in Wellhouse Lane, Barnet.

The staff member said: "When birds died, they are not being removed from the building. The problem is not being fixed but the hospital is trying to stop them from coming into the theatres.

"The other week, maggots were falling through the air vents in the ceiling between theatres one and two, about five feet away from the theatre. They were dropping like there's no tomorrow.

"I was standing there and we counted 50. I was shocked - operating theatres are meant to be the most sterile places in a hospital. If a maggot fell onto a patient during surgery and the wound was open, they could get an infection."

But a hospital spokesman said staff had found some dead pigeon remains in a part of the loft that was awkward to access, which is why the incident happened, but that it had all been cleared out and resealed.

He said: "In the past there was a problem that maggots had dropped through the ceiling into the theatres. "The ceilings were sealed up and the cracks were made airtight.

"What happened recently was that three maggots fell, not in the theatres but in the corridor. Within an hour of it happening, there were people in the roof checking everything. There has been absolutely no impact on clinical care."

He added that regular checks would take place and the hospital had employed the services of a hawk to scare pigeons away.

Alex Nunes, chairman of Barnet Hospital's Patient and Public Involvement forum, added: "It is pretty worrying. It's a very unpleasant accident, and I know the hospital has been very disturbed by it.

"We are very upset that such a thing could occur, but the hospital has done all it can to disinfect, clean and prevent a reoccurrence and stop the pigeons from getting in."