There are hopes that every adult in Britain might be vaccinated by the end of June after jab delivery accelerates to five million a week.
Senior government figures are reportedly growing more optimistic about the vaccine rollout and believe everyone over-18 may get the crucial jab in five months.
So far, the only target set has been to give the jab to all over-70s, care home workers and NHS staff by mid-February. The two million a week target appears to be on track after more than 324,000 doses were administered in the last 24 hours.
More than 3.5 million people in the UK have now received their first dose of a vaccine, Boris Johnson said, as he hailed those helping the "fantastic national effort".