In addition to distributing anti-viral drugs and vaccines, Dr Dermot Kennedy, of the Royal College of Physicians of Edinburgh, said that the need for the general population to have good "basic hygiene", particularly hand-washing, should be stressed.

Dr Kennedy, a consultant in infectious diseases in Glasgow, who is chairing a meeting of leading bird flu experts at the Royal College today, said stopping the practice of shaking hands when meeting someone would be a "good idea" and could act as a symbol of the need to keep them clean.

"It would raise eyebrows, but it would make a point," he said.

"We have always thought influenza transmission is through coughs and sneezes, but hands are becoming recognised as increasingly important.

"If people are sneezing all over the place and you put your hand on a strap in the underground and then to your mouth, you could be infected."

Dr Kennedy admitted that it was impossible to tell when a new flu pandemic would occur, and even if the current H5N1 strain would mutate into a disease that was capable of being spread from human to human, describing the flu virus as an "enigmatic imponderable".

However, Dr Kennedy said that at some point in the future there would be a new pandemic which could have devastating consequences.

The bird flu outbreak in 1918-19 killed between 40 million and 80 million people, but Dr Kennedy said a similarly infectious strain could cause far more deaths today.

"At that time the world’s population was 1.5 billion and now we are over four times that. If you equate that [death rate] to the current world population, it could be a quarter of a billion."

He added: "The difficulty with a new pandemic strain is the tendency it has to develop very quickly and overwhelm services. If you get a lot of people fulminatingly ill, in a critical, life-threatening state, within 24 hours of feeling unwell… I’m not sure we will be able to save those patients."