By Nick Triggle
Health reporter, BBC News
One in ten in the priority groups have been vaccinated
GPs need to go "full throttle" to get as many vulnerable patients as possible vaccinated against swine flu, the government's immunisations chief says.
More than 1m people in the UK have been vaccinated a month into the programme - one in 10 in the priority groups.
Professor David Salisbury said he would have hoped for more at this stage, but accepted doctors were doing their best.
It comes as the number of deaths in a week has hit a record high. The UK total now stands at 245 - up from 214.
This is a reflection of the fact that a greater proportion of people are ending up in hospital and in critical care than at the start of the pandemic.
However, latest figures show the number of new cases of infection is falling or remaining steady across the UK.
In England, there were 46,000 cases, down from 53,000. Scotland reported just over 21,000, almost the same as last week.
GPs said the immunisation programme was being slowed down because of the way the vaccines were being delivered to them.
Doctors have to mix the doses themselves because the vaccine has a 24-hour self-life.
However, each batch contains 10 doses, meaning GPs have to be confident they can vaccinate that many patients within a day or else the jabs have to be thrown away.
Dr Richard Vautrey, of the British Medical Association, said: "With seasonal flu we can vaccinate opportunistically - when patients come in for other appointments.
"But because of the way the swine flu one is being manufactured we have to make sure we have enough patients so the vaccine is not wasted.
"It is slowing it down, but to be fair I think it needed to be that way to get the amount we needed manufactured."
He also said the programme was taking time as some doctors would have only received their first batches in the last week or two.
However, there have also been suggestions not all the priority groups want the jab.
There are more than 11m people earmarked for it in the first wave, including pregnant women and people with health problems.
But there have been reports some areas are only expecting a 50% up-take, while a recent BBC survey found nearly half of people had doubts about vaccination.
The 1m-plus figure is based on data collected by 40% of practices in England.
Professor Salisbury said he was still hoping the initial groups would be completed in time for Christmas and urged GPs to go "full throttle".
He added: "Clearly I would have liked a bigger number, but that is what we have so far. I would like to see an acceleration now."
There are no overall figures for up-take among health and social care workers - about 2m are being offered the jab - although the government said anecdotal evidence suggested many were coming forward.