A MYSTERY illness which caused a school to close after more than 50 children became sick has been diagnosed as the 'flu.

Various tests have been carried out after the bug struck a fifth of the children at Mowden Junior School, Darlington, earlier this month.

Symptoms included fever, sore throats, stomach aches and coughing.

While an investigation to try to find the cause saw checks on the water systems by public health experts, Darlington Borough Council agreed to close the school as a precaution.

County Durham and Darlington Health Authority tested 18 of the ill children. Four of them tested positive for 'flu, leading the authority to believe this to be the cause.

A spokesman said: "They all had a very similar illness. Although only four out of the 18 tests showed a positive result, we can safely say it was flu." However, tests were still being carried out to find which strain of flu had been found.

A council spokesman said: "We are relieved that the illness has been identified and wish any youngsters still feeling its effects a speedy recovery.