Britain is donating a further 20 million Covid vaccine doses this year to poor countries struggling to immunise their populations.
A further ten million will be despatched in coming weeks.
Boris Johnson was due to tell a meeting on Saturday of world leaders at the G20 summit in Rome that they should work to get the whole planet innoculated against the disease by the end of next year.
“Like a waking giant, the world economy is stirring back to life. But the pace of recovery will depend on how quickly we can overcome Covid,” he was due to say.
“Our first priority as the G20 must be to press ahead with the rapid, equitable and global distribution of vaccines.”
Ministers stressed the latest donations will mean 30.6 million surplus doses of Oxford-AstraZeneca will have been given to poorer nations in 2021.
However, world health chiefs have heavily criticised wealthy nations for not being more generous and speedy in distributing their stockpile of jabs to poorer countries.
The UK has pledged to give 100 million doses of the vaccine.
It will donate at least 20 million more Oxford-AZ doses next year, meaning half of its total order of the vaccine will have been shared with countries whose vaccination programmes are still far behind.
All Britain’s 20 million Janssen doses will also go to COVAX as domestic need for the current booster programme will be met through mRNA vaccines and Oxford-Astra Zeneca.
The announcement of the extra donations came just hours after former Prime Minister Gordon Brown called on Western leaders preparing to gather at the climate change Cop26 summit in Glasgow to “make a decision” to provide the world’s poorest and most vulnerable people with Covid vaccines.
Mr Brown was among a group including former UN general secretary Ban Ki-Moon and ex-New Zealand premier Helen Clark who this week called for world leaders to send unused vaccines from the global north to the global south and keep vaccination targets on track.
Speaking on ITV’s Good Morning Britain, Mr Brown said of those due to gather in Scotland: “They’re the people who control these vaccines. Make a decision, get the unused vaccines out.”
A World Health Organisation plan to redistribute an over-supply of unused vaccines to the 92 vaccine-poor nations could deliver an extra 600 million doses to Africa and low-income countries as soon as December.
After noting that “partnerships work sometimes and they work quite well”, Mr Brown called on Western leaders to implement the plan.
“Nobody’s really safe until everyone’s vaccinated everywhere,” the 70-year-old told GMB.
“The disease is spreading in the poorer countries, it’s going to mutate, we’re going to have new variants like Delta, they’re going to come back to haunt even the fully vaccinated here.
“It’s in all our interests to get the vaccines all around the world to everyone.”
“Now the good news is we have the vaccines, we just need to get them out to people,” he added.
Oxford-AstraZeneca is the world’s most widely used vaccine, accounting for more than half of all COVAX deliveries.
Pharmaceutical giant AstraZeneca has committed to the distribution of the vaccine on a non-profit basis, with 1.5 billion doses having been used in more than 170 countries.