A Covid-19 vaccine from Oxford University and AstraZeneca has been approved for use in the UK, paving the way for mass rollout.

The jab, which has been described as a "game changer", was given the green light by the Medicines and Healthcare products Regulatory Agency (MHRA).

Health Secretary Matt Hancock said the approval is "fantastic news" and confirmed the rollout will begin on January 4.

He told Sky News: "I am now, with this approval this morning, highly confident that we can get enough vulnerable people vaccinated by the spring that we can now see the route out of this pandemic."

He said there would be a difficult few weeks ahead "but we also know that there is a route out of this".

He added: "The vaccine provides that route out. We have all just got to hold our nerve over the weeks to come."

Prime Minister Boris Johnson tweeted: "It is truly fantastic news - and a triumph for British science - that the @UniofOxford/@AstraZeneca vaccine has been approved for use.

"We will now move to vaccinate as many people as quickly as possible."

It comes amid increasing strain on hospitals in England, where the number of Covid-19 patients is the highest it has been during the pandemic.

Mr Hancock is due to announce any changes to tier areas in a statement to the Commons on Wednesday.

With case rates rising in all regions of England, and record patient numbers, any changes are likely to involve areas moving up a tier rather than down.

The UK has ordered 100 million doses of the Oxford University vaccine - enough to vaccinate 50 million people.

A Department of Health and Social Care spokesman said: "The Government has today accepted the recommendation from the Medicines and Healthcare products Regulatory Agency (MHRA) to authorise Oxford University/AstraZeneca's Covid-19 vaccine for use.

"This follows rigorous clinical trials and a thorough analysis of the data by experts at the MHRA, which has concluded that the vaccine has met its strict standards of safety, quality and effectiveness."