By Michael Bristow
BBC News, Beijing
Masked security guards patrol a quarantined hotel in Beijing
As more than 100 pupils and teachers on a cultural tour of China remain under quarantine at a hotel in Beijing, the authorities have been explaining their approach to tackling the spread of swine flu.
British school pupils have been quarantined in China because the country is employing strict controls to contain swine flu.
It is trying to prevent those infected from getting into China, and quarantines those with the H1N1 virus already inside the country.
China's Ministry of Health says these measures have proved more effective than those used by many developed countries.
So far there have been no reported deaths from swine flu in mainland China and only about 1,500 confirmed cases out of a population of more than 1.3 billion.
But the result of this policy is that many visitors - such as the British school pupils on a tour of China - have had to undergo a period of isolation.
"We understand that these British kids have come a long way to China and their parents back home must be very worried about their health," said a spokesman from Beijing Municipal Health Bureau.
But he added: "We as health authorities are taking all necessary medical procedures to prevent the spread of the disease according to relevant laws."
China's fight against swine flu begins at its ports and airports, where incoming passengers fill out forms asking if they have any flu-like symptoms.
One British pupil currently on a trip to China said a friend was taken away for extra checks after admitting on the form to having a runny nose.
People arriving in China also have their temperatures checked.
Many of those who display flu-like symptoms, including the British pupils, are taken to hospital for further checks, and kept there if they test positive for swine flu.
Others who have had contact with those infected are put into quarantine or under observation.
China's government allows its own citizens to isolate themselves at home, but foreigners are often quarantined in hotels - at the local government's expense.
China is concerned by its poor hygiene and dense populations
This has led to delays for many foreigners visiting China, including the mayor of New Orleans Clarence Ray Nagin, who in June was put into quarantine in Shanghai while on a business trip.
Many of the 700 British school pupils currently on a cultural tour of China are in a similar situation.
Some pupils are in Beijing Ditan Hospital, where many of the city's swine flu cases are sent. Others are in quarantine in Beijing's three-star Yanxiang Hotel.
Despite the difficulties faced by British school pupils, their morale seems high, at least among some of them.
One of them in Ditan Hospital, 19-year-old Joe Robinson, said he felt perky, despite testing positive for swine flu.
He spent Monday shut away in a room with two other young people suspected of having caught the virus. One of them was later released after tests came back negative.
"I've been ringing the [Yanxiang] hotel where the others are because they are also in isolation," he told the BBC by telephone.
He also gave an insight into just how serious the Chinese are taking the virus by revealing that his food is given to him through double doors that have a compartment between them.
Medical staff wearing protective clothing put the food in the compartment and then close the outside door before Mr Robinson is allowed to open the door on his side and collect the food.
China says it has to take these extreme measures because hygiene standards in the country are poor, particularly in rural areas.
It also cites the country's high population density as a reason for these strict measures.
China believes the low infection rate in the country so far shows these policies are working.
"Overall, the prevention and control measures have been more effective than many developed countries," the health ministry says on its website.