An outbreak of swine flu at a school in England saw the number of cases leap by 47 to 184, the British Department of Health said today.
Of the new cases, 44 were linked to the school in the West Midlands.
The remaining three patients, from London and the East of England, were either returning travellers or people linked to previously confirmed cases.
A Department of Health spokesman said: "The localised cases of swine flu found in the UK have so far been mild, and we have not seen evidence of widespread community transmission.
"Our strategy of containing the spread with anti-virals appears to have been effective in reducing symptoms and preventing further spread of infection.
"But we must not be complacent — it is right to prepare for the possibility of a global pandemic. The UK's arrangements are continuing to ensure that we are well-placed to deal with this new infection."
The Health Protection Agency said the newly-confirmed cases in the West Midlands involved 41 children and three adults linked to a continuing school outbreak.
So far 170 cases of the H1N1 virus have been confirmed in England, with 13 in Scotland and one in Northern Ireland.
Another 113 possible cases are being investigated.
PA