The UK will start donating vaccines to countries in need within weeks - with at least 100 million surplus doses being distributed in the next year, Boris Johnson announced.
The group of seven leading industrialised nations are expected to agree to provide a billion doses of Covid vaccine in an effort to end the pandemic in 2022.
The leaders – including US President Joe Biden – will spend the day discussing issues including the pandemic before a reception at the Eden Project attended by the Queen.
The Prince of Wales and the Duchess of Cornwall will be accompanied by the Duke and Duchess of Cambridge - who are taking part in their first G7 events.
Mr Biden has already promised to donate half a billion Pfizer vaccines for 92 low and lower-middle income countries and the African Union.
Under the Prime Minister’s plan, the UK will provide five million doses by the end of September, with 25 million more by the end of 2021.
What’s been said
The Prime Minister told the BBC: “I think that the people of this country should be very proud that of the 1.5 billion doses that are being distributed around the world to the poorest and neediest in the world under the Covax programme, one in three come from the Oxford/AstraZeneca deal that the UK did, allowing those vaccines to be distributed at cost.
“And that’s before we’ve talked about the £548 million that we’ve contributed to Covax, £1.6 billion to Gavi (the vaccine alliance).
“And, yes, we’re putting in five million doses by September, but we’ll do … 100 million before 12 months is out. That’s a huge number of extra doses.”
Boris Johnson has already hailed working with new US President Joe Biden as a “breath of fresh air” after the leaders’ first in-person meeting on 10 June.
Now, the Prime Minister will ask the G7 to encourage pharmaceutical companies to adopt the Oxford-AstraZeneca model of providing vaccines at cost price for the duration of the pandemic.
One fifth of the doses promised by Mr Johnson will be delivered through bilateral arrangements with countries in need while the rest will go through the Covax initiative which is distributing vaccines to poorer nations.
Downing Street said that by sharing five million doses in the coming weeks the UK will meet an immediate demand for vaccines for the countries worst affected by the pandemic without delaying completion of the domestic vaccination programme.
All adults in the UK will have been offered a first vaccine dose by the end of July under government plans.
At the summit, which runs until 13 June, the leaders of the UK, US, Canada, Japan, France, Germany and Italy will pledge at least a billion Covid vaccine doses to the world through dose sharing and financing.
They will also set out a plan to expand vaccine manufacturing in order to achieve that goal.
Pfizer, Moderna and Johnson & Johnson have already pledged to share 1.3 billion doses on a non-profit basis with developing countries.
Zoe Abrams, executive director at the British Red Cross, said the promise on vaccines was “heartening” but added: “While every commitment must be welcomed, more needs to be done, and fast.”
Additional reporting by PA.