Health chiefs are preparing to vaccinate the entire population against swine flu, it emerged today.

In what would be the biggest vaccination programme of the last 50 years, experts are already drawing up a priority list of patients to be given immunity before the bug becomes more virulent.

It comes after the first British patient without underlying health problems died after contracting swine flu, taking the number of swine flu-linked deaths in the UK to 15.

Peter Holden, the British Medical Association's lead negotiator on swine flu, told The Sunday Times: "The high risk groups will be done at GPs' surgeries.

"People are still making decisions over this, but we want to get cracking before we get a second wave, which is traditionally far more virulent."

He added: "If the virus does (mutate), it can get a lot more nasty, and the idea is to give people immunity.

"But the sheer logistics of dealing with 60 million people can't be underestimated."

The latest swine flu-linked death happened at Basildon and Thurrock University Hospitals NHS Foundation Trust, NHS East of England.

Chief Medical Officer Sir Liam Donaldson warned yesterday that other healthy people were at risk of dying from the disease.

He said: "As with all flu-like viruses, some people are at higher risk than others. Unfortunately, people who are otherwise healthy could also become seriously ill or, sadly, die."

But Sir Liam added: "Fortunately, this particular new virus isn't nearly as severe as it could have been.

"If it had, for example, come out of the bird flu variant it would have been producing much higher levels of mortality."

Yesterday holidaymakers were advised to check their travel insurance and keep in touch with tour operators as the bug sweeps across the UK.

With school terms ending and summer breaks approaching, people who contract the virus should take the advice of their doctors about whether to stay at home, according to travel association Abta.

Abta spokeswoman Frances Tuke said: "We have had calls about this with regard to insurance - apparently some insurers are placing exemptions on policies.

"If you need to cancel because of swine flu you need to check your travel insurance policy to ensure it is covered."

Nearly 10,000 Britons have gone down with swine flu after it spread to the UK from Mexico.

The UK has the third highest case total in the world after Mexico, with 10,262, and the US, which has at least 33,902.

:: The NHS advises anyone who thinks they might have flu to check their symptoms on or call the swine flu information line on 0800 1 513 513.