A school that was forced to shut after 103 children and four members of staff fell ill with a bug reopened yesterday.

There were still 40 pupils out of 317 absent from Blackhall Colliery Primary School, in County Durham, yesterday, but most were staying off in accordance with advice given from the Health Protection Agency (HPA).

Parents had been told that any children showing the vomiting and diarrhoea symptoms should be kept at home for 48 hours.

Headteacher Matt Younger said: "In 20 years of teaching, I have never known anything like it. While we usually have an outbreak of winter vomiting each year there has never been anything on this scale before.''

Last Monday, the school had had an environmental inspection and was given a clean bill of health.

Mr Younger said there had also been a large number of people in the wider community of Blackhall who had fallen ill with the virus. Extra precautions have been taken before the school was reopened.

Mr Younger said. "We have had the whole premises steam-cleaned and even had the carpets shampooed.''

A spokeswoman for the HPA said it now looked likely that it had been an outbreak of the virus known as winter vomiting.