All adults should be able to book their first Covid vaccine dose by the end of this week, the NHS England chief executive has announced.

Speaking at a conference on Tuesday morning, Sir Simon Stevens said: “I expect that by the end of this week, we’ll be able to open up the National Booking Service to all adults age 18 and above.”

It comes after Boris Johnson announced a delay to lifting England’s lockdown from June 21 to July 19.

The prime minister said the current rules needed to remain in place for an extra four weeks in a bid to avoid a huge third wave of Covid that would cost “thousands” of deaths.

 Johnson used a Downing Street press conference to tell the public it is “sensible to wait just a little longer”.

He said he while he was “confident” that no further delay will be necessary, he was unable to rule out another delay, warning of the possibility that an unforeseen and “far more dangerous” variant could emerge.

Under Johnson’s so-called “roadmap” out of lockdown, the fourth step involves the lifting of all remaining curbs including the rule-of-six guidance on gatherings, social distancing in pubs and theatres and the reopening of nightclubs.

But soaring cases of the Delta variant mean that two of the government’s four tests for unlocking – a low risk of the NHS being overwhelmed and the absence of new variants – cannot be guaranteed to be met.

In an attempt to win the race between the vaccination programme and the virus, all over-40s will also be offered a shorter waiting time between their two doses, with the gap cut from eight weeks from twelve. 

Everyone in the first 1-9 priority vaccination groups will also be offered their second dose by July 19.