Britain's flu crisis is now at epidemic levels, according to the Government's Chief Medical Officer.
Professor Liam Donaldson said that 300 people in every 100,000 now have the bug, and described Britain as being in the grip of a "serious epidemic".
The scale of the problem is thought to be much greater than statistics suggest because of the thousands of people calling the helpline NHS Direct - thus bypassing surgeries - and using drop-in health centres.
Prof Donaldson said there were probably twice as many people suffering from flu as official figures indicated, and that it had hit "epidemic proportions".
"There's a hidden element to this epidemic. We feel it's a lot higher and climbing. We think we are in for the big one," he told The Sunday Telegraph.
He added that there was also under-reporting of the outbreak because many "spotter" surgeries used to compile flu statistics were closed over the holiday.
A Department of Health spokeswoman said the official statistics showed there were currently 144 people in every 100,000 suffering from flu. As the usual gauge of an epidemic was 400 people in every 100,000, she said, the flu crisis was therefore not being officially treated as an epidemic by the Government.
But she added: "Professor Donaldson is happy to stick by his version that this is an epidemic. He believes it is many more than 144 per 100,000.
"It is very confusing and it depends on which definition you choose. Professor
Donaldson has looked at his graph and said it is a serious epidemic."