Britain's Health Protection Agency (HPA) announced on Monday that nine more cases of A/H1N1 flu has been confirmed in Britain, taking the total number to 27.

Five of the nine diagnosed with the H1N1 virus were seven-year-old pupils from Alleyn's School in London, a spokesman for the agency said. It is the fourth school to close.

Two other cases were London-based siblings of one of the pupils and two were adults who had visited Mexico. The siblings go to a different school but are related to one of the Alleyn's School pupils, the HPA said.

Environment Secretary Hilary Benn said the outbreak was less severe than first thought, but people should "play safe."

Information leaflets about how to reduce the chances of spreading infection are due to begin arriving in people's homes from Tuesday.