The NHS Covid-19 app will not have its sensitivity tweaked, Downing Street has confirmed, despite industries warning of staff shortages as England lifts almost all coronavirus restrictions.

Prime Minister Boris Johnson and Chancellor Rishi Sunak are among the hundreds of thousands of people currently self-isolating due to being alerted by NHS Test and Trace that they have come into close contact with a positive case.

Hospitality, leisure, food production and retail sectors have complained of having to close premises or cut opening hours because of the number of people being told to stay home for 10 days after being in contact with a person who has tested positive.

Andrew Lloyd Webber was among those to warn that “freedom day has turned into closure day” after the cancellation of performances of his West End show Cinderella.

But the Government said it does not plan to reduce the sensitivity of the app to avoid people being “pinged”.

The Prime Minister’s official spokesman, asked whether the app is working as expected, meaning it does not need tweaking, told reporters: “That’s correct.”

Speaking before a No 10 briefing, Business Secretary Kwasi Kwarteng said the number of workers being “pinged” by the NHS app is the “single biggest issue” being raised with him by company bosses.

He told LBC he accepts it is a “difficult situation” but said “there isn’t any movement on it”, and it will still be August 16 before there is a wider relaxation for those who have been had both doses of a Covid-19 vaccine.

Lord Lloyd-Webber criticised the “blunt instrument that is the Government’s isolation guidance” after a “rigorous” testing programme identified a positive case among the show’s cast.

“We have been forced into a devastating decision which will affect the lives and livelihoods of hundreds of people and disappoint the thousands who have booked to see the show,” he said in a statement.

“Cinderella was ready to go. My sadness for our cast and crew, our loyal audience and the industry I have been fighting for is impossible to put into words.”

The House of Commons was also affected, with Speaker Sir Lindsay Hoyle warning a “large number” of people have been contacted to isolate including his deputy, Dame Rosie Winterton, who he said was pinged by the app.

Nick Mackenzie, chief executive of hospitality chain Greene King, told BBC Radio 4’s Today programme that 33 of his pubs were shut last week due to workforce shortages, leading him to call for a test and release scheme for those testing negative.

PureGym boss Humphrey Cobbold told the programme that the country has become the “United Pingdom”, with one in four of his staff notified to quarantine.

Mr Johnson’s spokesman said the Government will “constantly review” issues around critical workers and key infrastructure, after an exemption for frontline NHS and social care workers who are double vaccinated and test negative for the virus was brought in this week.

The Prime Minister will lead a virtual press conference on Monday afternoon from his official country residence, Chequers, to mark the lifting of restrictions in England, a decision that has come under fierce criticism from political leaders.

Labour leader Sir Keir Starmer branded the wholesale unlocking “reckless”, while Scotland’s First Minister Nicola Sturgeon said talk of “freedom day” is “not sensible” given the UK is recording around 50,000 new Covid cases per day.

A further 39,950 lab-confirmed cases were announced in the UK on Monday, along with an additional 19 deaths within 28 days of a positive Covid test.

The decision to take the final step of the road map out of lockdown means face masks are no longer mandatory in shops and on public transport, limits on gatherings have gone, and the work-from-home guidance has ended.

Nightclubs, theatres and restaurants can fully reopen, while pubs are no longer restricted to table service only.

Professor Andrew Hayward, a member of the Scientific Advisory Group for Emergencies (Sage), stressed that if the public do not take a cautious approach to their rediscovered freedoms, the country could “move into the mid and high tens of thousands of deaths” in what he called the “biggest wave of Covid infection that we have ever seen”.

The UK Government has again called for caution after people queued to return to nightclubs in the early hours of Monday.

The Prime Minister’s spokesman said: “We continue to urge nightclubs to use the Covid pass to enable them to check whether people have been double jabbed or have had a recent negative tests – I think that’s in their interests and the interests of those attending.”

The possibility of making the use of Covid passes compulsory would be considered “if necessary”, he added.

Meanwhile, in Scotland, the devolved administration has decided to drop coronavirus measures to the lowest level of its five-tier system.

Face coverings in shops and public transport will remain mandatory for “some time to come” while social distancing will reduce to one metre inside public places as the shift to Level 0 kicks in, Ms Sturgeon confirmed.

It came as No 10 faced further pressure over the Prime Minister’s initial intention to skip quarantine measures after being alerted that he had come into close contact with Health Secretary Sajid Javid, who tested positive for the virus over the weekend.

The Conservative Party leader and the Chancellor, who was also told to quarantine, decided to take part in a testing pilot to avoid the requirement to self-isolate but quickly U-turned on Sunday after a public backlash.

Vaccines minister Nadhim Zahawi told ITV’s Good Morning Britain an error had been made in choosing the testing regime and that the “Prime Minister realised that this would be wrong”.

Mr Johnson’s spokesman insisted the “correct process” for self-isolation had been followed, with the Prime Minister staying put at Chequers after being alerted by Test and Trace that he was a close contact of a positive case.

The spokesman gave different answers when asked when the Prime Minister travelled from Downing Street to Chequers, first telling reporters it was at the “start of the weekend”, then Friday morning, before changing it to 3pm on Friday.

Since isolating, Mr Johnson has tested negative for the virus and is showing no symptoms, the official said.

Mr Johnson will quarantine until July 26, which will include the final Prime Minister’s Questions before the Commons goes into recess, and the two-year anniversary of him entering No 10, which is on Saturday.