Britain could donate a fifth of its Covid-19 vaccine supply to poorer countries and remain on track to vaccinate all adults by the end of July, analysis by Unicef suggests.
The UN children's fund said the UK would have enough excess supply to inoculate 50 million people globally with two doses – a total of 100 million doses – even after every adult in the UK was vaccinated and a third booster dose given to high-risk groups.
This figure could rise to 200 million surplus doses if all the Covid-19 vaccines the UK ordered were approved by the medicines regulator.
Britain has secured more than 500 million doses of seven vaccines for a population of 66 million. These include those developed by Pfizer-BioNTech, Oxford-AstraZeneca and Moderna, which are approved for UK use.
Joanna Rea, director of advocacy at Unicef UK, urged Prime Minister Boris Johnson to commit to donating excess doses ahead of the G7 summit in England next month.
“We can’t ignore that the UK and other G7 countries have purchased more than a third of the world’s vaccine supply, despite making up only 13 per cent of the global population, and we risk leaving low-income countries behind,” she said.
“Unless the UK urgently starts sharing its available doses to ensure others around the world are protected from the virus, the UK will not be safe from Covid-19.
"Our vaccine success could be reversed and the NHS could be fighting another wave of the virus due to deadly mutations.”
France, a G7 member, previously committed to donating 5 per cent of its vaccine supply to the Covax initiative, a health partnership that delivers doses to poorer countries.
French President Emmanuel Macron called on the US and the rest of Europe to do the same.
"We're not talking about billions of doses immediately, or billions and billions of euros," he told the Financial Times.
“It’s about much more rapidly allocating 4 to 5 per cent of the doses we have.
"It won’t change our vaccination campaigns, but each country should set aside a small number of the doses it has to transfer tens of millions of them, but very fast, so that people on the ground see it happening.”
Britain has committed £548m ($744m) to Covax but was accused recently of vaccine hoarding, as many nations struggle to secure access to doses.
The Covax initiative has delivered just 59 million doses across the globe to date – and less than two per cent of the world's Covid-19 vaccines have been administered in Africa.
A spokesman for Mr Johnson this month said the UK had no excess doses to donate at that stage.
"We committed in February to sending excess doses from the UK's supply to the Covax procurement pool and to countries in need once they are available," he said.
"Right now, we are moving through the UK prioritisation list for our domestic rollout and we don't have surplus doses but … we will keep this under review."
In April, Covax said a "very big push" was needed to achieve the goal of delivering two billion doses to poorer nations by the end of the year.
“It’s not all smooth sailing and we are facing a number of challenges,” Covax chief Aurelia Nguyen said.
Former UK prime minister Gordon Brown warned of a "man-made catastrophe" if poor nations remained unvaccinated, while his predecessor Tony Blair said those countries could become "isolated from the world".