Foreign Secretary Dominic Raab has dismissed renewed calls for an early easing of the coronavirus lockdown, saying the outbreak was still at a “delicate and dangerous” stage.

With Boris Johnson arriving back in Downing Street on Sunday evening, ministers have come under intense pressure from senior Tories to relax the strict social-distancing measures, amid concern at the damage they are doing to the economy.

The Prime Minister returned to No 10 after recovering from Covid-19 at his country home Chequers, and will chair Monday’s morning meeting of the Government’s coronavirus “war cabinet”.

But Mr Raab, who has been standing in for Mr Johnson while he recuperated, said the Government would proceed “cautiously” in order to avoid a second peak in the outbreak.

“We are at a delicate and dangerous stage,” he told Sky News’s Sophy Ridge on Sunday programme.

“We need to make sure that the next steps are sure-footed, which is why we are proceeding very cautiously and we are sticking to the scientific advice.”

He was backed by the NHS England medical director Professor Stephen Powis, who said while the number of patients in hospital with the disease was continuing to fall, it could easily pick back up if the restrictions were relaxed.

With some DIY centres starting to re-open and draw in weekend shoppers, Prof Powis expressed concern that the data showed a “slight uptick” in the numbers of people out on the roads.

“My fear is that those curves won’t continue to be on a downward trend, but will start to go on an upward trend. We are not at a point where any of us can be absolutely confident that that’s not going to be the case,” he told the daily No 10 news conference.

“We need to remind ourselves that this has been a really tough four weeks and we don’t want to lose the benefits that have come from this. We need to keep going.”

His warning came at the end of a weekend which saw the coronavirus death toll in hospitals pass the 20,000 mark with fears that many more have died in care homes, hospices or in the community.

According the latest official figures, a total of 20,732 patients had died in hospital after testing positive for coronavirus in the UK as of 5pm on Saturday, up by 413 from the day before.

Mr Johnson returned to No 10 after two weeks convalescing at Chequers. Prior to that he spent a week in St Thomas’ Hospital, including three nights in intensive care.

Even before he was back in London, he was facing calls from a series of wealthy Tory backers who have donated millions of pounds to the party coffers to begin lifting the lockdown to allow the economy to start up again.

Financiers Michael Spencer and Peter Hargreaves, the banker Sir Henry Angest, Phones4u founder John Caudwell and restaurateur Richard Caring all told The Sunday Times they wanted to see some re-opening of the economy.

Steve Morgan, the former boss of the housebuilder Redrow, told the paper: “We’re actually in danger that the medicine – if you want to call the lockdown that – is more harmful than the cure.”

Mr Raab, however, said that while the Government had been doing it’s “homework” in readiness for the time when restrictions could be eased, people would have to get used a “new normal”.

“We won’t just have this binary easing up of measures. We will end up moving to a new normal,” he told BBC1’s The Andrew Marr Show.

“We need to take a sure-footed step forward which protects life but also preserves our way of life. So we are very focused on doing the homework that can allow us to do that.”

He said it was “inconceivable” schools could re-open without measures in place to stop the spread of the disease, but said ministers were looking to ease restrictions on outdoor activities.

“We do want to look – when it is safe, when it is responsible – at ways to allow more outdoor activities to take place, but again we have got to have the evidence that that is a sure-footed step – doesn’t allow coronavirus to get a grip back on the country.”

He said officials were also looking at possible sea and airport checks, with passengers arriving in the UK required to quarantine for 14 days.

It is believed that it could form part of the Government’s “test, track and trace” policy to isolate new cases of the disease, further curbing its spread, as the numbers come down.

“Whether it is a quarantine period, or testing or other measures that might be taken, it is possible,” he said.

“I ask this question every week – ‘Can we check there aren’t measures at the border at the current level of the coronavirus challenge that we face that would make a difference?’ We will keep asking that question.”

Meanwhile, First Minister Nicola Sturgeon warned she could delay any lifting of the restrictions in Scotland if she thought the Government at Westminster was moving too quickly.

“If, and it is an if, I’m not saying that we’re likely to get in to this territory, the UK Government took decisions that I thought were premature in terms of coming out of the lockdown then clearly I would want to make sure that Scotland did what I judged was best to protect the population,” she told The Andrew Marr Show.