The first children in Britain have started receiving a swine flu vaccine as part of a major new trial.

Researchers are hoping to use about 1,000 youngsters over the next fortnight to see which of two different drugs perform the best.

The children, aged between six months and 12 years, are being recruited at five test venues in Oxford, Bristol, Southampton, Exeter and London.

One vaccine being used - Pandremix, made by GlaxoSmithKline (GSK) - has been approved by European regulators.

Another made by Baxter is still being considered by the European Medicines Agency but could get approval this week.

Head researcher Professor Andrew Pollard, of the University of Oxford, said: "We are doing this trial to compare head-to-head the two vaccines which are going to be used in the UK against swine flu to see which one works best in children and which one is best tolerated.

"We are sort of in a race against time because we know the flu season is already started. We hope to immunise the children over the next ten days or so."

The most recent data from the Government showed the number of swine flu cases across the country almost doubled in a week, from an estimated 5,000 to 9,000, prompting speculation a second wave of infections could be on its way.

The Government is hoping to start vaccinating millions of people in high-risk groups, such as those with asthma and diabetes, and health workers, next month.

Across the UK, 82 deaths have been linked to the virus, with 70 in England, nine in Scotland, one in Wales and two in Northern Ireland.