Health Minister Matt Hancock has said Britain is in talks with Oxford and AstraZeneca for additional doses of their Covid-19 vaccine that has been changed to better target the "beta" coronavirus variant first identified in South Africa.

"We've started commercial negotiations with AstraZeneca to secure a variant vaccine: future supplies of the Oxford AstraZeneca vaccine that have been adapted to tackle the B.1.351 variant first identified in South Africa," Hancock said in a speech at Oxford University.