The Prime Minister’s announcement represents a significant speeding up of the vaccine rollout.
The Government’s previous target had been to provide first doses to adults by September.
Under the revised plans, all adults aged 50 and over, as well as younger people with underlying health conditions, will now be offered their first jab by April 15.
The Prime Minister said in a statement: “Hitting 15 million vaccinations was a significant milestone – but there will be no let up, and I want to see the rollout go further and faster in the coming weeks.
“We will now aim to offer a jab to every adult by the end of July, helping us protect the most vulnerable sooner, and take further steps to ease some of the restrictions in place.”
The Government plans to publish its “roadmap” out of lockdown on Monday, paving the way to a return to some semblance of normal life.
Mr Johnson was keen to street that the lockdown easing would be “cautious and phased.”