Experts are clearly extremely concerned about the new swine flu virus which the World Health Organisation warned today has the potential to cause a pandemic.

Dr Alan Hay, director of the World Influenza Centre in London, told me this afternoon that we must take this seriously: "It looks pretty ominous, one has to say. It's difficult to look on the bright side at the moment." He stressed, though, that it's still early days, there's a lot we don't know and he doesn't want to be alarmist.