The H1N1 swine flu virus which swept the globe last year has returned to Britain with 10 people dying in the last six weeks, health officials said on Saturday.

Britain's Health Protection Agency said the 10 deaths had occurred in adults all under the age of 65, most of whom had underlying health issues.

"Over the last few weeks, we have seen a rise in the number of cases of seasonal flu both H1N1 (2009) and flu B in the community," Professor John Watson, head of the HPA's respiratory diseases department, said in a statement.

"We have also received reports of patients with serious illness requiring hospitalisation and outbreaks of flu in schools across the country."

H1N1 flu broke out in March 2009 and quickly spread across the world. The World Health Organisation said about 18,450 people died from the virus, including many pregnant women and young people.

WHO declared the pandemic over in August.

Watson told the Independent newspaper Britain appeared to be at the "vanguard" of the latest outbreak with other European countries beginning to see some swine flu cases.

The HPA said it was often the case that a pandemic strain became the most common seasonal strain during the next flu season, so it was not surprising to see the return of H1N1 (2009).

An HPA spokeswoman said there had been an increase in the number of flu cases being reported at doctors' surgeries across Britain but this was to be expected over the winter months.

"In terms of actual numbers of cases of flu, it's nothing unusual," she said.