He said the plans would mean preparing facilities to be able to produce 30 or 40 million doses of the vaccine in the first instance, as well as expanding production of the vials used to contain them.

The global competition for vaccines meant shortages of such products, he stressed, meaning a “big and powerful partner” was needed in order to compete.

Asked if Britain would get first priority if the vaccine succeeds, he said that around 30 million people who are vulnerable would be given the first round of jabs, but said Oxford was already talking to partners overseas to ensure they could also make it available quickly.

“We are very conscious of the fact that we do not want a lag in the availability of this vaccine between developed countries and developing countries,” he said.

He said the pharmaceutical company had been “enormously generous” in their proposals which would mean the vaccine will be made and distributed essentially at cost”.

AstraZenenca chief executive Pascal Soriot said the company would supply the vaccine at cost for the duration of the pandemic and said he hoped that there would be "several vaccines available to supply the needs of various countries around the world."

Mr Soriot told BBC Radio 4: "It is definitely a risk to launch into development of this vaccine, but now is the time to take those risks - this is a terrible crisis we're facing, and we need solutions.

“And a vaccine, of course, is the number one tool we can bring to manage this epidemic.”

He added: “We should know relatively soon if it does work.

“By June or July we will already have a pretty good idea of direction of travel in terms of its potential efficacy.”