British airlines have put into effect measures to stop people with swine flu boarding flights in a bid to prevent the virus from spreading further.

British Airways said there had been a “very small number of cases” where people who had checked in with symptoms of H1N1 had been advised not to travel after having medical checks.

Virgin Atlantic also said victims would not be allowed to board one of its planes without a fit-to-fly certificate from their doctor or a hospital, though there had been no cases yet.

The World Health Organization declared the virus a global pandemic June 11. More than 120 countries have reported cases of human infection. About 98,000 cases have been documented worldwide, with 440 deaths, according to the WHO.

With 29 deaths and a huge rise in the number of cases, Britain has the worst swine flu figures in Europe.

Medical screening for the swine flu virus has been introduced at many airports around the world for passengers arriving on international flights but there are concerns that many people may not be aware they are infected.

Those who do have symptoms have been advised by Britain’s health authorities to delay their journeys until the signs have cleared up.

BA told CNN Monday though that it was “business as usual” and all flights were operating normally.

Virgin Atlantic spokesman Paul Charles said: “If there are signs of something being wrong, be it excessive sneezing or coughing, not looking well, high temperature, then the airport staff can call in a medical team for extra advice.

(Source: CNN)