"It's the protection of vaccines that will ultimately allow us to reclaim our lives and get the economy moving again," Prime Minister Boris Johnson said after the approval by the UK's independent medicines regulator.
But he urged the public to remain cautious on the day that England exited a four-week lockdown and re-imposed regional curbs.
Health Secretary Matt Hancock said that starting with care home residents and health and care staff, Britain's National Health Service will begin with 800,000 doses "early next week" and ramp up to "millions" of inoculations by the end of the year.
"Help is on its way," he told BBC radio. "We can see the dawn in the distance but we have to get through to the morning," Hancock added, underscoring the appeal for the public to continue adhering to social restrictions.
England's chief medical officer, Chris Whitty, also welcomed the "excellent news" but stressed, "It will take until spring until the vulnerable population who wish to are fully vaccinated. We can't lower our guard yet."
The breakthrough will encourage hopes the world can finally get back on course in 2021 after a year of traumatic losses, both human and economic.
The novel coronavirus has killed nearly 1.5 million people since the outbreak emerged in China 12 months ago. At least 63 million cases have been registered.