Downing Street has insisted it is still “crucial” to self-isolate when told, after a minister said people could ignore the NHS covid app if they wanted.

Paul Scully, a business minister, said on Tuesday morning  it was “up to individuals and employers” to decide what to do when pinged by the app.

But No.10 quickly slapped down the suggestion. “Isolation remains the most important action people can take to stop the spread of the virus,” a spokesperson said.

“Given the risk of having and spreading the virus when people have been in contact with someone with Covid it is crucial people isolate when they are told to do so, either by NHS Test and Trace or by the NHS covid app.

“Businesses should be supporting employees to isolate, they should not be encouraging them to break isolation.”

Speaking to Times Radio earlier, Scully had said: “The app is there to give… to allow you to make informed decisions.

“And I think by backing out of mandating a lot of things, we’re encouraging people to really get the data in their own hands to be able to make decisions on what’s best for them, whether they’re employer or an employee.”

Asked whether this meant people should or should not self-isolate if pinged, he said: “We want to encourage people to still use the app to be able to do the right thing, because we estimate it saves around 8,000 lives.”

But he added that it was “up to individuals and employers”.

John Edmunds, professor of infectious diseases at the London School of Hygiene and Tropical Medicine and a member of Sage, warned contact tracing and self-isolation still play an important role in “stopping cases getting out of control and preventing deaths”.

“We have one of the highest rates of cases in the world right now. The NHS has been under strain for a long time and they are busy trying to catch up on operations and are very, very busy. So to put them under more pressure now is going to be awkward,” he said.

It comes as Boris Johnson faces a backlash over his plans to make coronavirus vaccination compulsory for nightclubs and other crowded venues in the autumn.

Clubs, backbench Tories and opposition MPs criticised the PM’s announcement on Monday – the day that clubs in England were allowed to open for the first time since March last year.