If it is proven to work and to be safe, it will be rolled out to priority groups – including health and social care workers and those most at risk of coronavirus – in the early months of next year, the Department for Business, Energy and Industrial Strategy said.
It is the fourth different type of potential coronavirus vaccine the government has now signed up for.
Alok Sharma, the business secretary, said: “Our scientists and researchers are racing to find a safe and effective vaccine at a speed and scale never seen before.
“While this progress is truly remarkable, the fact remains that there are no guarantees.
Some 60 million doses of a potential Covid-19 vaccine could start to be made available in the first half of 2021 after the government struck a deal with the two pharmaceutical giants behind it.
The jab is being developed at pace by GlaxoSmithKline and Sanofi Pasteur with human trials set to begin in September.
“In the meantime, it is important that we secure early access to a diverse range of promising vaccine candidates, like GSK and Sanofi, to increase our chances of finding one that works so we can protect the public and save lives.”
No vaccine has yet been proven to offer immunity against the deadly virus, which has killed more than 650,000 people worldwide since emerging in China in December.
But governments across the planet are signing deals for millions of doses of candidate vaccines in the hope one of them proves effective.
The new UK agreement follows previous deals made with AstraZeneca to produce 100 million doses in partnership with the University of Oxford; with BioNTech/Pfizer for 30 million doses; and with Valneva for 60 million doses.