The Prime Minister's pledge to donate 100 million surplus Covid-19 vaccines to poor countries has been welcomed by Christian Aid.
Boris Johnson made the announcement as G7 leaders gathered in Carbis Bay, Cornwall, for the start of their summit.
He said: "As a result of the success of the UK's vaccine programme, we are now in a position to share some of our surplus doses with those who need them.
"At the G7 Summit, I hope my fellow leaders will make similar pledges so that, together, we can vaccinate the world by the end of next year and build back better from coronavirus."
US President Joe Biden has already promised to donate half a billion Pfizer vaccines to countries in need.
G7 nations have been under pressure to share their surplus vaccine supplies after launching successful vaccine rollouts at the same time as developing countries have struggled.
Christian Aid policy director Patrick Watt welcomed the Prime Minister's pledge but said more was needed to end the pandemic.
"We need much greater ambition if we're to vaccinate the world," he said.
"Best estimates are that a billion vaccines need to be given to poorer countries this year. And if we're to significantly boost production and lower costs, the Prime Minister needs to join Presidents Biden and Macron in supporting a patent waiver.
"Increasingly, Boris Johnson and Angela Merkel are out of step with a growing international consensus that pooling of intellectual property and know-how is needed, given the scale of the crisis."
In the run-up to the summit, Christian Aid and religious leaders like the Dalai Lama and Rowan Williams called on the G7 to address vaccine inequality as a vital step towards ending the pandemic.
In an open letter, they said that although 900 million doses have been administered to date, low-income countries account for just 1% of these. More affluent countries account for more than 83%, they said.
They also called for vaccine patents to be waived in order to increase supply.
Watt added, "Boris Johnson's decision that the UK will share some of its excess pre-orders is a welcome step on the road to tackling the vaccine apartheid which has so far seen less than 1% of the one billion doses going to the poorest countries.
"Hoarding while vulnerable groups in poorer nations remain unvaccinated is morally indefensible and will delay the end of the pandemic."