LONDON - Fourteen Britons who had contracted H1N1 flu have died and the rapid spread of infection in two areas of the country is close to epidemic level, health officials said on Thursday.

The Department of Health said Britain now had 9,718 laboratory-confirmed cases, the third most in the world behind the United States and Mexico.

Britain's Chief Medical Officer Liam Donaldson said the actual number of cases was likely to be higher.

All 14 who have died had underlying health issues and it was not clear in how many cases the patients had died as a direct result of the virus, known as swine flu.

In London and the West Midlands we are getting pretty close to epidemic levels. We've seen big surges there, Donaldson told

BBC TV.

For the country as a whole, the average is about the level of the flu season but in some parts of the country the levels are getting pretty big.

The World Health Organization declared on June 11 that the outbreak of the virus was a pandemic and more than 94,500 cases have been reported worldwide.

Health Minister Andy Burnham said last week the government was projecting more than 100,000 new cases a day of the flu by the end of August.

While most people who have caught the infection have suffered mild symptoms, in a small minority it has proven more severe.

The Department of Health said that 335 people in Britain were currently in hospital after contracting the infection, with 43 of those described as critical.

Donaldson said there were no signs the virus was becoming more virulent, although he warned it could mutate.

It does tend to affect people with underlying illnesses quite severely and a small number of healthy adults can get the severe complications of flu but the majority of them get a mild illness, he said. (Reporting by Michael Holden; Editing by Louise Ireland and Steve Addison)