All adults aged 50 and over should receive a coronavirus vaccine by May, Downing Street has confirmed.

Ministers have previously refused to give a firm date, saying only that the “ambition” was to vaccinate the first nine priority groups “by the spring”.

However, amid signs of confusion in Whitehall, the Cabinet Office issued a press notice on Friday morning stating the UK vaccination programme planned to reach all nine priority groups by May.

It said the rollout of the programme meant that local elections could go ahead in England and Wales on May 6 as planned.

But less than three hours after it was released, Downing Street said it had been issued “in error” and was being withdrawn – only to row back a few minutes later and confirm it was correct.

In a chaotic online briefing for political journalists, a No 10 spokesman said: “This was issued in error. I believe the Cabinet Office have now withdrawn it.”

But when pressed again on the issue, the spokesman said: “It isn’t actually being withdrawn.

“We have confirmed today that the elections must go ahead. The Government is supporting that delivery with funding and plans that they take place in a way that is Covid secure.

“The Cabinet Office document is correct.”

The spokesman said Boris Johnson would set out a “precise timeline” when he publishes the Government’s roadmap for lifting lockdown restrictions in England on February 15.

Under new rules set out by the Cabinet Office, voters will have to wear face coverings inside polling stations and will be asked to bring their own pen or pencil to mark their ballot when they go to vote on May 6.

Proxy voting rules will also be changed so that people who have to self-isolate can request an emergency proxy vote up to 5pm on polling day.

“Super Thursday” in May is set to see a bumper set of elections taking place across Great Britain – including a number of contests postponed from 2020 because of the coronavirus pandemic.

In London, there will be elections for the mayor and assembly, which were originally due to take place last year.

Across the rest of England and Wales, voters will be choosing a mixture of councillors, local mayors, regional mayors and police commissioners.

Voters in Scotland and Wales will also be choosing new parliaments – though a decision on whether these will go ahead will be made by their respective governments.