BORIS Johnson will signal this evening that Britain will have to endure the restraints of the coronavirus lockdown for months to come with only a gradual easing of some measures beginning over summer.

The three-week review due next Thursday is expected to keep most if not all of the restrictions in place until the Whitsun holiday at the end of May. The formal announcement will be based on advice given by the UK Government’s SAGE group of scientific and medical experts.

The Prime Minister, who is chairing his first Cabinet today since returning to work, will lead this evening’s daily press conference from Downing St and while he will not reveal a detailed roadmap on an exit strategy, he will give a sense of direction on the way forward.

Mr Johnson will stress the importance of avoiding at all costs a second peak of the virus, which would result in more deaths and deliver an even bigger economic hit to the country.

He is also expected to issue a personal thank-you to the NHS for saving his life and pay another tribute to Captain Tom Moore, who turned 100 today and saw his fund-raising efforts for the NHS reach £30 million. The centenarian was honoured this morning with a flypast from a WW2 Spitfire and Hurricane.

Last night, Nicola Sturgeon set the tone for what is to come from Mr Johnson later today when she told ITV’s Peston programme: “People talk about lifting the lockdown, that is not going to be a flick of the switch moment; we're going to have to be very careful, very slow, very gradual.

“I'm far from convinced at this stage that when we get to the next review point on May 7, we'll be in a position to lift any of these measures right now because the margins of manoeuvre that we're operating in right now are very, very, very tight and narrow."

Robert Buckland, the UK Justice Secretary, echoed the point, stressing there would not be a "sudden" move into the next phase of the lockdown.

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He said the First Minister was "right to be cautious," saying: “The common thread between the Governments is one of extreme caution following the evidence of the Sage committee, making sure that we don't do anything in a premature way that could risk a second spike. That would be a disaster."

Mr Buckland said there was already a lot of work going on within Whitehall “as to what the future is going to look like; it would be a dereliction of duty if we didn't do that”.

He added: “We need to be absolutely sure that the five tests that were set out some weeks ago are going to be met, and in particular the need to avoid that second or even third spike in the disease is clear to me both in terms of health and the well-being of the economy as well."

The gradual shift is likely to include strict social distancing and enhanced hygiene measures in shops, on public transport and in workplaces. Companies will be urged to ensure workers will continue to work from home where possible and to stagger any commutes into their places of work. While the advice in Scotland is for people to wear masks and face coverings in restricted public places, it remains unclear as to whether the UK Government will follow suit in England.

Meanwhile, Mr Buckland admitted the Government would “probably” not meet its goal of 100,000 daily coronavirus tests but praised colleague Matt Hancock for being "bold" in setting the target.

Whitehall’s view seems to be that setting the target was the right thing to do as it focused people’s minds in increasing capacity; others believe it was a deliberate distraction from criticisms of the Government’s performance on supplying Personal Protective Equipment.

Mr Buckland insisted that, notwithstanding any failure to meet the tests target today, the Government was "well on its way" to hitting the number and the UK Health Secretary deserved praise "even if the target isn't met today".

It came as NHS Providers, which represents hospitals and NHS trusts in England, described the target as a "red herring," which has distracted attention from failings in the long-term Covid-19 strategy.

Its Chief Executive Chris Hopson said as many as 120,000 tests would be needed daily for NHS workers once the UK came out of lockdown to stave off a second wave of the virus.

With just over 52,000 tests carried out on Tuesday, the Government must make up a huge gap to achieve the goal before Friday.

Speaking on BBC Breakfast, Mr Buckland acknowledged the target could be missed, adding: "Even if it isn't met, we're well on our way to ramping this up and 100,000 is an important milestone, but frankly we need more.

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"Yes, 52,000 isn't 100,000, I know that but we are straining every sinew to get there.

"If he[Mr Hancock] hadn't set a target, he would have been criticised for being unambitious. Now is the time in respect of this to be bold; being brave is something we should acknowledge even if the target isn't met today."

Mr Hopson said NHS staff and patients would need to be tested regularly to control the spread of the virus once lockdown measures are eased.

With 800,000 people working for the NHS, Mr Hopson said there would need to be between 110,00 and 120,000 tests a day for them to be tested once a week.

Speaking to BBC Breakfast, he added: "There are still health and care workers showing symptoms who are not able to get tests because we are still struggling with capacity and some of the testing centres are too far away."

Mr Hopson urged the Government to update its coronavirus strategy and to make good its promise to increase testing capacity.