The British National Health Service (NHS) is to begin its coronavirus vaccination programme on Tuesday, according to NHS chief executive Chris Hopson in an interview with the BBC.
Prime Minister Boris Johnson called the programme the largest vaccination campaign in British history.
Some 800,000 more doses are expected to arrive next week, with millions to be delivered by the end of the year.
On Wednesday, Germany's BioNTech announced its vaccine, created with US drug company Pfizer, had been approved by Britain's Medicines and Healthcare Products Regulatory Agency (MHRA) for emergency use.
The vaccine is to be administered first to people living or working at care homes as well as people over 80 and health personnel especially at risk.
The vaccine would first be rolled out at 50 "hospital hubs" across the country, due to the logistical challenges of storing it at minus 70 degrees Celsius.
In review by US and EU agencies
Britain is the first country to approve the Pfizer/BioNTech vaccine, which is currently also being reviewed by US and EU regulators.
The British government has hailed the vaccine's rapid approval as a success, but experts from the EU and the US have expressed criticism of the emergency approval, including the top US infectious disease expert, Anthony Fauci.
Fauci rowed back on Friday after he said on a US podcast that the British regulator had "rushed" its approval of the vaccine.
Fauci said in a BBC interview on Friday that he had great confidence in the scientific and regulatory processes in Britain. However, he emphasized that the process in the US had to be more rigorous - because of the high level of skepticism among the population there about vaccines.
Britain is one of the countries that has been particularly hard hit by the pandemic. According to official government figures, more than 60,000 people have now died after being infected with the coronavirus. Experts believe that the actual numbers are even higher.
