All adults in the UK will be offered their first dose of a coronavirus vaccine by the end of July, the prime minister has pledged.
More than 17 million people have been given a jab since the UK's Covid vaccine rollout began in December 2020.
But Boris Johnson said he now wants the programme to "go further and faster".
He said the July target would allow vulnerable people to be protected "sooner" and would help to further ease lockdown rules across the country.
NHS England chief executive Sir Simon Stevens said there were "early signs" the vaccine rollout was contributing to a fall in hospital admissions.
The PM is due to hold a final meeting with senior ministers about how to ease England's lockdown later, before he sets out the full "road map" on Monday.
A speedy rollout of the vaccine to all vulnerable people is seen as critical to reducing the pandemic's death toll and relieving pressure on the NHS.
The government's previous target was to offer all adults the first dose by September.
The new plan means that by 15 April, all adults aged 50 and over, as well as younger people with underlying health conditions that put them at higher risk, should have been offered a jab.
However, the order of priority for under-50s has yet to be outlined by the Joint Committee on Vaccination and Immunisation (JCVI).