FOUR in 10 Britons could catch the deadly swine flu virus within the next six months, leading health officials said last night.

Professor Neil Ferguson, a member of the World Health Organisation (WHO) taskforce, said 40% of people in the UK could be infected if the country was hit by a pandemic.

But Prime Minister Gordon Brown said Britain was “among the best-prepared countries in the world” and added that the Government was taking “all the urgent action that is necessary” to help prevent the spread of the virus.

Merseyside holidaymakers were last night rearranging their trips to Mexico as flights were cancelled to avoid the spread of the virus.

The UK’s major tour operators have suspended all flights to the country, and people already in resorts such as Cancun are being offered early flights home.

Local travel agents say Mexico is a popular destination with Merseysiders, especially at this time of year.

All flights from Manchester to the country have been cancelled until at least Friday, and a Cancun passenger at the airport was met by staff from the Health Protection Agency (HPA) yesterday morning, after feeling unwell.

She was later allowed home, where she will be monitored.

Travel consultant Tracey Haworth, from Going Places, in Walton Vale, said: “We have had quite a few customers affected.

“Anyone who is travelling to Cancun is entitled to a full refund or we can arrange another holiday to a different destination.

“It is gutting, a lot of people have been upset because they had their heart set on Mexico, but others just still really want to go away and have chosen another holiday.

“Anyone who is travelling up to May 6 with Thomas Cook gets priority, and then those up to May 22.