School closed after pupil catches virus and infects four classmates

Lessons halted at fourth school as the number of confirmed cases reaches 27

An independent school has closed because of swine flu after five pupils were diagnosed with the infectious disease.

Alleyn's School in Dulwich, south-east London, will be shut for at least a week after a Year Seven student who went on an Easter holiday to America passed the illness to four friends. The Health Protection Agency (HPA) said it was unclear whether the pupils, who returned to class last week, had spread the H1N1 virus to other classmates.

All the children and staff have been offered antiviral drugs and will be able to collect them in person this morning.

In a statement posted on the school's website, the headmaster Colin Diggory said he was aware that the closure would cause "particular concern" to students who were due to take exams this week. He said the school would be contacting exam boards to arrange the rescheduling of Year 13 art exams and Year 12 modern language oral exams.

Last night another London school, The Dolphin School in Battersea, also shut its doors after two of its pupils fell ill. Billed as a "precautionary measure", it is the fifth school closure in wake of the virus.

The Alleyn's pupils were among nine new British swine flu cases confirmed yesterday. Two other children who tested positive are siblings based in London and close contacts of a previous case, the HPA said. The other victims are adults – one from London and another from the West Midlands – who recently returned from Mexico.

Meanwhile, the private South Hampstead High School for girls, in north London, has also been closed after a 14-year-old pupil was confirmed with the H1N1 virus on Sunday. She caught it from someone who had travelled to Mexico. Antiviral drugs have been offered to her year group, arrangements are being made for exams and the school will not re-open until at least Thursday.

South Hampstead High said on its website that the 14-year-old, from Barnet, was "at home and well".

The HPA had recommended that the school's leavers' ball, scheduled for Sunday night, should be abandoned as a precaution. But The Independent understands that the event went ahead under the guise of a private party, without the knowledge of staff.

Attendees were asked to sign a disclaimer before entering the party, held in Portland Place, central London. The headmistress, Jenny Stephen, sent text messages to parents urging them not to speak to reporters.

The two other schools closed on the orders of the HPA are Downend in Bristol, where 210 Year Seven pupils were issued with the antiviral drug Tamiflu on Friday. Two days before that, Paignton Community and Sports College in Devon was closed and 340 pupils were issued with Tamiflu.

Swine flu has now been confirmed in London, Newcastle, Oxfordshire, Devon, Merseyside, Worcestershire, Gloucestershire and central Scotland. The HPA said it was awaiting test results on 300 further suspected cases.

An 11-year-old girl from south-west London and a man from Ayrshire have also contracted the disease, it emerged at the weekend.

Several Britons also remain under quarantine in a Hong Kong hotel after a guest there was confirmed as China's first swine flu case. Eddie Sweeney and his wife Terry, from Buckinghamshire, checked into the Metropark Hotel for two nights on Thursday but were told the following day that they would be confined to the building for a week.

"It is very frustrating", Mr Sweeney said. "Effectively we are in our rooms, apart from going to collect meals. Otherwise, we are confined."

5: The number of Year 7 pupils at Alleyn's School in Dulwich, south-east London, who were confirmed with swine flu yesterday