The Oxford vaccine is expected to be approved within days of Christmas, kickstarting a massive drive to give jabs to millions of people in January, The Telegraph can reveal.
Senior Whitehall sources believe the Medicines and Healthcare Regulatory Agency (MHRA) will authorise the vaccines on December 28 or 29 after final data is provided to the regulator on Monday.
Football stadia and other sites across the country will then be opened from the first week of January, to allow mass vaccinations on a scale never seen before in the UK.
However, the progress comes amid growing fears that England is about to enter a third lockdown, with the Prime Minister recently refusing to rule out following Wales and Northern Ireland in such a course of action.
Last week the NHS began the first Covid-19 vaccination programme in the world, with jabs given to around 140,000 elderly people and health and care workers in the first seven days.
This week the rollout has expanded far more widely, with around 400 GP centres now involved, as well as 83 hospitals.
Over the weekend, the total number of Britons who have received the jab is expected to pass the 500,000 mark, The Telegraph understands.
By next week, more than 200,000 people a day should be receiving jabs, equating to well over one million doses a week by Christmas.
Once the Oxford jab gets the green light, the opening of mass vaccination centres will mean this can be increased to several million doses a week, Whitehall sources say.
It means Britain is on course to vaccinate the 20 million most vulnerable people by March, allowing far greater release of restrictions, with the prospect the whole country could be vaccinated by summer.
However, the progress comes amid increasing infections, and pressure on hospitals.
On Friday, Boris Johnson was asked whether England would follow Northern Ireland, which is introducing a six-week lockdown from Boxing Day.
He said: "We're hoping very much that we will be able to avoid anything like that. But the reality is that the rates of infection have increased very much in the last few weeks."
Britain has ordered 100 million doses of the vaccines, four million of which are immediately available, allowing a major expansion in the NHS vaccine programme across the country.
Unlike the Pfizer jab, the Oxford vaccine can be stored in regular refrigerators, meaning it can be administered far more easily, from thousands of sites across the UK.
Authorisation by the MHRA will also give confidence to countries across the world. India has already manufactured more than 50 million of the AstraZeneca vaccines.
The NHS has drawn up plans for “large scale” vaccination sites, in football stadiums, racecourses and conference centres to start administering jabs from the first week of January.
The programme will also be expanded to high-street pharmacies, while the number of GP sites involved in the programme will continue to expand.
The rapid rollout of the programme has seen some teething problems this week, with some GPs complaining that deliveries have been cancelled with little notice, while others say they have been offered more jabs than they can keep up with.
However, health officials hope that the authorisation of the Oxford jab will prove a “game-changer”, allowing vaccines to be transported and administered far more easily.
Although the first batch of four million doses will be delivered from the Netherlands and Germany, the bulk of manufacturing will take place in this country, allowing for easy access.
AstraZeneca has said a further 15 million doses of active ingredients are ready, and can be filled into vials in a matter of days.
The full order of 100 million doses, in addition to 40 million doses of the Pfizer jabs being imported from Belgium, is enough to vaccinate the whole country. The speed of rollout means the majority of those aged 80 and over are likely to receive the Pfizer vaccine, which was authorised first.
Both types of vaccine require two doses, with a three-week gap between them for the Pfizer one, and a four-week gap for the AstraZeneca vaccine.
The AstraZeneca vaccine has taken longer for regulators to assess, because of differences in the efficacy rates found in different groups, ranging from 62 to 90 per cent. However, a study released this week suggests that leaving an adequate gap between doses is the most crucial way to boost efficacy.
