Plans to vaccinate everyone in the UK against pandemic 'flu once a potentially-fatal strain emerges have been announced by the British government.
Britain's Chief Medical Officer Sir Liam Donaldson said 120 million doses - the equivalent of two per person - would be needed to cover the population.
But he said the vaccine could not be created until the exact strain in a future 'flu pandemic was known.
This means that many people could already be struck down with pandemic 'flu before the vaccine is available for use, which could take up to six months.
He said that the UK would be "very lucky" not to have pandemic 'flu arrive here from elsewhere in the world before the vaccine was produced.
But he said it would still help a lot of people who would otherwise get 'flu.
The government is inviting vaccine manufacturers to tender for "sleeping contracts", which would mean they had to build up capacity to meet demand once the strain is identified.
Sir Liam said they were not revealing details of the expected cost of the contracts, but they would negotiate to get the best price possible.
The vaccination announcement was made as the Department of Health published its updated Pandemic Influenza Contingency plan.