The US-based company's vaccine was shown to have 94% efficacy against COVID-19 in final trials.

Seven million doses had already been ordered by the UK government with a further 10 million expected to follow - but it will likely not become available until March.

This is because it is being manufactured in the US at first, and will take a few months before manufacturing facilities in Europe will be ready to distribute.

News about the jab, which will be available for free, was welcomed by Health Secretary Matt Hancock.

He called it "another weapon in our arsenal to tame this awful disease", and added it will "boost our vaccination programme even further once doses become available from the spring".