A search for the source of a maggot infestation at the Royal Children's Hospital in Aberdeen will continue over the weekend. Specialists brought in by NHS Grampian health chiefs resumed their investigations on Friday and said they would continue over the weekend.

The discovery has caused the closure of three operating theatres, and postponements of procedures. Two operating theatres in a children's hospital remained closed yesterday after being infested by maggots.

But a third theatre at the Royal Aberdeen Children's Hospital was given the go-ahead to reopen for emergencies.

NHS Grampian said specialists would continue their probe over the weekend and revealed two "decontamination cleans" had been carried out.

A spokesman added: "The source is not believed to be in the theatres and the search is focusing on the roof space."

The most likely cause is believed to be that a bird has managed to get into the roof space and died.

Around 25 maggots were found by cleaners on the floor of theatres, some singly and some in clusters, apparently at various stages of development.

"Clearly infestation of this kind is very unpleasant, and our advisors will continue to try throughout the day to identify the source. I am satisfied this is not a reflection on staff or standards of cleanliness in the hospital."