The huge sum is the most given by any country so far and brings the UK’s overall donations to £544 million. Some £210 million of the international development budget money will pay for research into a vaccine.
Millions will also be spent on developing affordable treatments for coronavirus patients, new testing devices and an international hygiene programme.
The funding will ensure British scientists and researchers continue to lead the global fight against the virus.
The Prime Minister yesterday urged world leaders during a virtual G20 summit that more needs to be done to speed up vaccine development.
Mr Johnson said: “While our brilliant doctors and nurses fight coronavirus at home, this record British funding will help to find a vaccine for the entire world.
“UK medics and researchers are at the forefront of this pioneering work.
“My call to every G20 country and to governments around the world is to step up and help us defeat this virus.
“In the meantime, I want to repeat to everyone that they should stay at home, protect the NHS and save lives.”
The UK, along with many other countries, is channelling funding to the Coalition for Epidemic Preparedness Innovations (CEPI) which is supporting the development of vaccines that will be available throughout the world.
Future vaccines will be made available at the lowest possible price to the NHS and other countries’ healthcare systems.
CEPI says it needs $2 billion (£1.6 billion) additional funding from international governments to develop the crucial vaccine.
If all G20 governments pledged $100 million (£82 million) funding this shortfall would be met instantly.
The UK has already gone beyond its share by committing more than half-a-billion pounds to CEPI.
The video call between G20 leaders, the first gathering of this group since the coronavirus outbreak, also discussed international efforts to protect the global economy from the long-term effects of the virus.
Britain has led the way in responding to the economic impact of coronavirus, producing a huge and unprecedented programme of support both for workers and for business in the UK and contributing to the IMF fund to support vulnerable economies.
The additional package of UK aid announced today will go towards producing rapid tests for coronavirus and testing and developing medicines to treat the disease, for use in the UK and around the world.
Health experts say that quickly identifying those with coronavirus and having the means to treat those most affected will be pivotal in bringing down the number of people killed by the virus.
UK funding will accelerate the development of medicines to treat the virus, both by testing the effectiveness of existing medicines against coronavirus, such as drugs currently used in cases of malaria, and by researching and testing new treatments.
International Development Secretary Anne-Marie Trevelyan said: “This UK Government support will be vital in efforts to find a coronavirus vaccine and treatments, which will ultimately help stop its spread around the world.
“We are backing experts, including in the UK, to find solutions as quickly as possible to this pandemic. This will ultimately help us to save lives in this country.”