More than 300 people are in intensive care with flu, Government figures showed today.
Data from the Department of Health for England revealed there were 302 people in intensive care beds.
It is unclear how many have swine flu but they are expected to be in the majority.
New figures on the number of deaths from flu and swine flu will be released by the Health Protection Agency on Thursday.
Health Secretary Andrew Lansley briefed Cabinet colleagues this morning on the flu situation and told them the NHS had plenty of capacity to deal with the upsurge in cases.
Prime Minister David Cameron told a press conference at 10 Downing Street: "We had a report at Cabinet this morning from the Health Secretary about the situation as regards flu, and particularly swine flu.
"He gave a report about the number of critical care beds being used for people with flu. While obviously... the number of flu cases has doubled in the last week, there is still plenty of capacity in the NHS.
"I think the figures on flu are are quite similar to two years ago. They are a little worse than last year.
"I think there is a very good grip in the Department of Health on this issue. Andrew Lansley has a great grip over that department."
Mr Cameron said he did not know whether his wife Samantha had been advised of the risk of swine flu to pregnant women while she was carrying their fourth child, Florence, who was born earlier this year.