In a back street in Bristol, wedged between a series of graffiti-covered nightclubs and a backpacker hostel ("beds from £15 a night"), sits one of Britain's 19 swine flu nerve centres.

From this nondescript office, dozens of call-centre workers — some with only a day's dedicated training — will offer thousands of diagnoses a day.

Along with other centres in Southwark, South London, and Plymouth, phones are also being manned by staff in Bangor and Newry, Northern Ireland, and Cardiff and Swansea — despite the service being open only to patients in England.

In Bristol, staff who usually take calls for the passport service, debt collectors and corporate customer services will, for an extra pound an hour, be authorising the release of antiviral drugs for the next six months. "I'm tempted by the overtime but it's a big responsibility, isn't it?" one said. "You could be talking to people with serious illnesses."

Many temporary workers have also been hired, spending the past few weeks preparing for yesterday. Two former students said they had loved their first day on the hotline. "It's great fun, a great job. It's a real buzz when you're helping people," one said.

The centre is one of several run by Teleperformance, a private contractor that has contracts with government departments and large companies. Workers have been given strict instructions not to talk about their jobs but, under cover of a neighbouring office furniture depot, The Times had a quiet word with some of them.

One worker, whose usual job is fielding queries for people interested in becoming teachers, said he was due to start work on the hotline after only a day's training. "It's intensive, so I should be all right," he said.

Having worked for the company for several months, the young man said he was ready to take whatever the virus-ridden public had to throw at him. "I am a bit nervous, but I'm looking forward to it — the people you get are much more wideranging than the Training and Development Agency. And it pays better."

Workers can expect to make about £7 an hour. Others said the hotline was little different from their regular work. "It's the same sort of thing, isn't it? Just answering calls, and the computer does a lot of it," one woman said.