The death toll linked to swine flu has risen to 31 as the Prime Minister said the Government was making an "enormous effort" to tackle the pandemic.
New figures out on Wednesday are expected to show a jump in the numbers of people contacting their GP with the flu, as well as those dying with the virus.
Gordon Brown insisted "robust plans" were in place to fight it and measures were being taken in a "calm and organised and ordered way".
More than 700 people worldwide are known to have died after getting swine flu which the World Health Organisation says is spreading faster than any previous flu pandemic.
The UK pharmaceutical giant GSK said that first batches of its vaccine would not be available until September, with further shipments in 2009 and 2010.
The Government has ordered up to 132 million doses of the vaccine from GSK and another drug company, Baxter.
GSK admitted it was charging around £6 per dose to developed countries but said it "did not recognise" figures suggesting it only costs the firm £1 per dose to produce.
A spokeswoman said: "We will be charging approximately seven euros but obviously that varies from country to country."
She said the firm had "absolutely no idea" where the £1 figure came from. The cost of producing the drug would be greater than the seasonal flu vaccine because it contained an additional ingredient - an adjuvant - designed to make it more efficient, she said.
"We are not disclosing the cost but one thing that is worth bearing in mind is that normal vaccines do not include the adjuvant that is in the H1N1 vaccine," she added. "We have invested a huge amount of money in the technology to develop it so it makes sense that it would not be something that is really really cheap."
