When Patricia Hewitt blamed doctors for the shortage, she sparked off a row over where the missing flu vaccine could have gone.

The British Medical Association said the Government had moved the goalposts by expanding the definition of the at-risk groups who have priority for the flu jab after GPs had placed their orders last February and March.

A total of 14 million doses were ordered for the UK, which the health department claimed was well in excess of the number in the at-risk groups - the elderly and people with chronic conditions such as asthma and diabetes - who numbered 11 million in England.

But in a letter sent on 25 July the Government's chief medical officer, Sir Liam Donaldson, told GPs that carers of the elderly and those at risk would also qualify for the jabs.

Jim Johnson, the chairman of the BMA, said: "There is a huge number of carers and there was no stock for them. It is clearly not the GPs' fault if the Government moves the goalposts after they have put their orders in."

Family doctors had a financial incentive to reserve their flu vaccine stocks for the elderly and at-risk groups because they are paid £7.51 for each jab plus a sliding scale payment up to a maximum of £3,700 if they vaccinate all eligible patients. No payment is made for vaccinating other groups and GPs cannot offer the vaccination privately.

Ms Hewitt suggested yesterday that GPs may have been giving the vaccine to the "worried well". Mr Johnson said: "It is unlikely they are immunising those not in the at-risk groups because they don't get paid for it."

The health department rejected claims by the Conservatives that the inclusion of carers in the at-risk groups had expanded the numbers eligible for the vaccine by 5 million and said stock for at-risk groups had been increased by 27 per cent this year.