Britain's winter flu outbreak worsened suddenly last week with 10 new deaths reported, figures published yesterday show. Total deaths since the start of the current outbreak in October now stand at 27, putting the country at the head of the European league.

The Health Protection Agency (HPA) said that 24 of the 27 deaths were from H1N1 swine flu and three from influenza B. The victims included 18 adults under 65 and nine children.

Only one of those who died is known to have had the anti-flu jab. Vaccination rates are low and specialists urged people in at-risk groups, such as children and pregnant women, to have one. The HPA said the vaccine was 70-80 per cent effective and the deaths did not indicate a "vaccine failure".

The increase in severe cases in the last fortnight is also putting the NHS under pressure. The HPA said 19 patients were receiving extra corporeal membrane oxygenation (ECMO) treatment, given to the worst affected victims whose lungs have failed.

This is 60 per cent higher than the maximum number treated on ECMO machines at the peak of last year's pandemic. England has just 21 ECMO beds available for flu in five hospitals around the country.

This year's flu outbreak appears to be accelerating faster than in 2009-10. Figures published on Wednesday by the Royal College of GPs showed a near tripling of cases in the community to 87 per 100,000 of the population.

Seasonal winter flu is usually most severe in elderly people, but swine flu targets a younger generation. Only a small minority are severely affected.

Professor John Watson, head of respiratory diseases at the HPA, said the outbreak of swine flu had been expected and a "very substantial wave of activity" was not likely. Older adults of 50-plus have some protection against swine flu and up to a third of younger adults and half of children are thought to have caught the virus last year and thus have immunity.