Prime Minister Boris Johnson is due to unveil long-awaited plans on how lockdown measures will be eased in England.

However, four key tests will need to be met as restrictions are gradually relaxed across the country over the coming weeks.

Here is how it will work, based on what we know so far:

– How are restrictions going to be eased?

The changes are expected to be rolled out in four stages.

Before each new step the Government will look at the Covid-related data to assess what impact the relaxing of measures has had so far.

Mr Johnson said the Government will be “cautious” in its approach.

– What conditions must be met?

The Prime Minister said his road map will contain four tests for easing restrictions at each stage.

The Government will assess the success of the Covid-19 vaccine rollout, whether they are reducing hospital admissions and deaths, infection rates and the impact of any new coronavirus variants.

Such data will be used to determine whether the next stage of restrictions should be lifted.

– Are we meeting those tests?

The Government has said the four tests are currently being met.

– What restrictions will be lifted first?

Mr Johnson is due to tell MPs on Monday that all pupils in all year groups can go back to the classroom from March 8, with outdoor after-school sports and activities also allowed to restart.

It is also understood that, from March 8, people will be permitted to have socially distanced one-to-one meetings with others outdoors in a public space.

This means friends and family members could sit down for a coffee or have a picnic in the park, something not currently allowed under lockdown.

The Telegraph also reported that care home residents will be allowed a single visitor from this date.

– What next?

It is expected that larger groups will be allowed to gather in parks and gardens from March 29.

The “rule of six” will return, along with new measures allowing two households, totalling more than six people, to meet.

Outdoor sports facilities such as tennis and basketball courts are also set to reopen at the end of next month.

Organised adult and children’s sport – including grassroots football – can return.

Guidance asking people to remain in their local area will also be lifted, the Telegraph reported, meaning families could drive somewhere to go for a walk.

– What about pubs and non-essential shops?

The longer-term picture of the Government’s plans is not yet clear.

Various reports suggest hospitality could return at some point between the Easter weekend and May, with an initial focus on outdoor provision.

The Telegraph reports that April is the earliest pubs and restaurants are likely to be allowed to reopen, with service only permitted outdoors.

– Will restrictions be eased in some parts and not others?

Measures will be eased, step by step, across the whole of England at the same time because the virus is viewed to be fairly uniformly spread across the country.

– What do the experts say?

Professor Sir David Spiegelhalter, a member of the Scientific Advisory Group for Emergencies (Sage), said the Government will have to leave room for “highly local” interventions.

He told Times Radio on Sunday: “I think they are going to have to keep the possibility of having much more targeted interventions in certain areas.”

Fellow Sage member Professor John Edmunds has said rapid easing could lead to a surge in hospital admissions “and indeed deaths”, and placed emphasis on vaccinations.

He told the BBC’s Andrew Marr Show: “We’re all at risk and we can all spread the virus, and so, until we’ve all been vaccinated – I include children here – then there is going to be significant risk of a resurgence.”