The number of British people infected with swine flu increased to 27 yesterday and two more schools had to close, bringing the total to five.

The private Alleyn’s School, in Dulwich, southeast London, confirmed yesterday that a total of six pupils aged 11 and 12 in Year 7 had tested positive for the H1N1 virus. Dolphin School in Battersea, southwest London, also closed as a precautionary measure after two children, siblings of one of the sick pupils at Alleyn’s, contracted the virus.

One pupil at Alleyn’s had visited the United States during the Easter holidays and five others had contracted the disease. All were responding well to treatment. Another pupil, aged 7, is being tested as a further suspected case.

The Health Protection Agency ordered the £13,437-a-year school to close and last night every member of staff and the parents of every pupil was issued with the antiviral drug Tamiflu. One parent, Cornelia Miller, 45, a psychotherapist, confirmed that her daughter, Zoe, 7, was ill and was to be swabbed for the virus. She said that her daughter did not know the other children who had fallen ill.

Pupils and parents were most concerned about the impact on this year’s GCSE, AS and A2 public examinations. Colin Diggory, headmaster at Alleyn’s, said that he was contacting the relevant examination boards to reschedule the A-level foreign language orals and art practical examinations that were due this week. The school will reopen next Monday.

Year 12 students said that they were concerned about the effect of the closure on their exams. Charlotte Bailey-Wood, 17, has French and Spanish oral exams in the next fortnight. She said: “I’m in my last year and the last thing I want is to catch anything that will hold me back from doing my best. It’s just really shocking because it’s the last thing that you expect happening to your school.” Matthew Syrett, 17, said: “If exams are put off it gives us more time to revise at home, but we miss quite a lot of material that we could cover with the teachers in that time.”

Other schools affected are the independent South Hampstead High School in northwest London, Downend School in Gloucestershire and Paignton Community and Sports College in South Devon.

There are 23 cases in England, including 13 in London. Two of the new cases are adults, one from the capital and one from the West Midlands, who visited Mexico recently. There are four cases in Scotland and a fifth, a woman from Fife, is now being tested after showing symptoms. She had travelled on flights from Los Angeles to London and then on to Edinburgh last Thursday but, as she was not showing symptoms during the journey, there seemed no pressing need to trace other passengers on the aircraft.

A spokesman for the Department of Health said: “The arrangements in place across the UK are continuing to ensure that we are well placed to deal with this new infection.”

Alan Johnson, the Health Secretary, said in a BBC interview that he expected a second more serious wave of cases later this year.

The World Health Organisation said that it was still monitoring the spread of the disease on every continent but no decision had been taken to raise the pandemic level from five to six, the maximum. Dr Keiji Fukuda, assistant director-general at the WHO, said that there were particular concerns for the southern hemisphere, which was approaching winter, when flu cases were most common.

The WHO said that there had been a total of 26 deaths out of 1,025 confirmed cases in 20 countries.

Mexico, which has been in almost complete shutdown, is to start lifting restrictions slowly. Restaurants and cafés will reopen in Mexico City tomorrow and libraries, museums and churches on Thursday. Cinemas, theatres and bars will remain closed and there is no decision on reopening schools and businesses.

Several Britons are still in quarantine at a Hong Kong hotel after a guest became China’s first confirmed case of swine flu.

The Department of Health swine flu information line is 0800 1513513.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• How I lost the gift of joy for a while
• Why Ann Widdecombe has got it wrong
• Alas, it’s the end of the road for petrolheads