All adults aged 50 and over should receive a coronavirus vaccine by May, the Government has announced.

Ministers had previously refused to give a firm date, saying only that the first nine priority groups would be vaccinated by the spring.

Downing Street repeatedly declined to define when spring ends during a briefing for journalists on Thursday.

But the Cabinet Office announced on Friday morning that the Government intended to vaccinate all nine cohorts by May.

It said the UK’s vaccination programme planned to have reached all nine priority cohorts by May – which it said gave the Government confidence to commit to holding local elections that month.

According to the Government’s vaccines delivery plan, some 27 million people in England – and 32 million people across the UK – are estimated to fall in the first nine groups.

The Government is on track to vaccinate the first four cohorts by February 15 – including NHS and care home staff, care home residents, and all those aged 70 and over.

So far, more than 10.4 million people in the UK have received their first dose of a coronavirus vaccine.

Categories five to nine include all those aged 50 and over, as well as adults aged 16-65 in an at-risk group.

Prioritisation for the rest of the population has yet to be determined.

NHS chief executive Simon Stevens said on January 11 that groups five to nine would get the jab by the end of April.

He told MPs: “This is a sprint to mid-February, and then it will be a sprint from mid-February through to the end of April to extend the vaccination to the rest of the higher risk groups.”

Sir Simon added there would then be a “marathon” to inoculate the under-50s “into the autumn”.