A MINISTER has been slapped down by Number 10 after suggesting it was "up to individuals" to decide whether to self-isolate after being "pinged" as a contact by the NHS Covid-19 app.

Downing Street said it was "crucial" for people to quarantine in line with the app's recommendation, just hours after business minister Paul Scully suggested people should make an "informed decision" about whether to obey the technology.

He said self-isolating after being told to by the app was a decision for individuals and employers.

Another minister in the business department, Lord Grimstone of Boscobel, stressed in a letter to one large employer that the app was only an "advisory tool" and that people were not under any "legal duty", The Times reported.

Although it has never been a legal requirement to obey the app's instructions, the official NHS guidance has been that people should "self-isolate immediately" when told to.

A No 10 spokeswoman said: "Isolation remains the most important action people can take to stop the spread of the virus.

"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."

Earlier, Mr Scully told Times Radio: "It's important to understand the rules. You have to legally isolate if you are on the... contacted by Test and Trace, or if you're trying to claim isolation payments.

"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."

However, he added that it was "up to individuals and employers".

On Monday night, Boris Johnson had stressed the importance of self-isolation as "one of the only shots we have got left in our locker to stop the chain reaction of the spread of Covid" following the lifting of England's restrictions.

Professor Sir Jonathan Montgomery, who chaired the ethics advisory board for NHSX on its contact tracing app, told Times Radio the Government needed to give clearer guidance to people about what to do when told to self-isolate.

"When we had no protection the risk was the same for everybody. If that risk is now reduced because someone is double-vaccinated, it feels as though we need more sophisticated advice," Sir Jonathan said.

"If we are visiting an elderly relative or a cancer patient then take the ping seriously, but if you are doing something relatively Covid-friendly, then maybe make a different decision."

Labour hadow health minister Justin Madders said: "The Government is making it up as they go along.

"Ministers mix messages, change approach and water down proposals when the public and businesses need clarity and certainty."

It comes after Prime Minister Boris Johnson and Chancellor Rishi Sunak were forced to U-turn over self-isolation at the weekend. 

No 10 initially said they would not have to isolate after coming into contact with Health Secretary Sajid Javid, who had tested positive for coronavirus, as they were taking part in a pilot scheme involving daily testing instead.

However this decision was reversed following widespread outrage, with opposition politicians claiming it was "one rule for them and another for the rest of us".