Out of the 60 children at Portsdown Primary School in Portsmouth who have been tested so far, 36 have shown signs of exposure to the disease.

They will be given precautionary antibiotics and further tests to establish if they have the full-blown disease.

The other 250 children and staff at the Cosham school will be given tests early next week.

Health officials confirmed on Thursday that the 10 to 11-year-olds were to undergo tests and chest x-rays to check whether they had the disease.

Portsmouth City Council, which had known about the infection since 19 January, wrote to parents saying that the school would carry on as usual.