Chief medical officer Sir Liam Donaldson has said latest figures show a ‘small increase’ in the number of new swine flu infections.

Last week, the number of new cases stood at an estimated 84,000 - an increase of 6,000 on the previous week.

Sir Liam said there had been a reduction in the number of young people contracting the disease.

Speaking through a video link from Washington, he explained: “This could be a half-term effect - we can’t be completely sure - so, before starting to talk too much about the overall flattening off and even a slight reduction, we’ve got to wait a week or two to see what happens.”

He added, however, that there had been a rise in swine flu patients in critical care. Of 848 people in hospital with the virus, 172 are in intensive care.

Sir Liam said there had been a “snowballing” of critical care cases over the last few weeks.

The death toll in the UK has reached 154, with 105 in England, eight in Wales, 31 in Scotland and 10 in Northern Ireland.