Pharmacies in Tower Hamlets don't stock Tamiflu these days. The east London borough has Britain's highest swine flu rate, and the drug is only available at a secret distribution center.
Up to 400 people flock every day to the centre, near the working-class district's Mile End hospital, which is on the frontline of the swine flu pandemic gripping Britain harder than any other European country.
"We've got more swine flu cases per head of population than anywhere else in England. That means we're experiencing it first," said Dr. Douglas Russell, medical director of the National Health Service (NHS) in Tower Hamlets.
"We've experienced significant additional pressure but I think everyone is coping," said Russell.
The infection rate in Britain as a whole almost doubled last week, with an estimated 100,000 new cases, while at least 30 people with the virus have died, in a scenario which could be repeated in other European countries, experts say.
To limit the spread, health authorities are asking people with the A(H1N1) virus to stay at home, and send a so-called "flu friend" to fetch the precious anti-viral drug.
Tower Hamlets, which has a large young population and Britain's biggest Bangladeshi community, is pulling out all the stops to advise people how to avoid swine flu, and what to do if they think they have it.
Mosques have been making announcements after prayers, while leaflets in English, Bangladeshi and Somali have been distributed to back up a media campaign telling people not to go out if they suspect they have the virus.
Only people who have been positively diagnosed are being given Tamiflu, and pharmacies have been asked to give back their stocks of the drug, which can only be distributed at the official centres.
"I've seen an influx of people, on a busy day 350 people, on a quieter day 200," said nurse Lindsay Collins, taking packets of Tamiflu pills from a cupboard kept under lock and key.
"People are generally anxious, there is a lot of concern in the community out there," she added.
In the corridors there are disinfectant dispensers, although staff don't wear any particular protection.
Despite the advice to send a friend to collect the Tamiflu, people with swine flu still turn up at the centre. They are taken into a separate, isolated room, given a face mask and then examined and given the drug if needed.
Mr. Islam, a 25-year-old Bangladeshi, turns up to collect Tamiflu for his 12-year-old niece. The family called a doctor, who confirmed the diagnosis and faxed a prescription to the centre.
"We contacted the GP (General Practitioner), he called us back, they sent a prescription to this centre. It went all right," he said.
Domenico Santamaria, a teacher from a town in central Italy who is in London with 34 pupils on a school trip, has had to come to the centre several times -- five children from his group have caught the virus.
"This is a big problem, as you can imagine they are very worried. Some parents are panicking," even if the infection is not serious, he sighed.
To lighten the workload on hard-pressed doctors the government on Thursday launched a telephone hotline and Internet service allowing people to get Tamiflu without speaking to a medical practitioner.
The website crashed within minutes of launching, according to media reports, but appeared to be working normally late Thursday.
The government reported "unprecedented demand" for the site, which received around 2,600 hits per second or 9.3 million an hour on its first day.