Health Secretary Matt Hancock said there are currently around 5,000 to 7,000 unknown positive cases of coronavirus in the country.

Asked what would result in the test and trace self-isolation system being made mandatory, Mr Hancock told BBC Breakfast: “Obviously we’re going to track very carefully the proportion of people who do what they are instructed to do by the NHS.”

In response to a viewer raising GDPR concerns, Mr Hancock added: “There are very strict confidentiality rules that are in place.

“Actually, in practice, we’ve found that only a tiny proportion of people have that sort of reaction.”

Asked who will pay someone’s wages if they have to self-isolate more than once, Mr Hancock said: “The onus is on employers … when you’re instructed to go home by the NHS that is equivalent to being off ill and we did put in place support much earlier in the crisis to deal with this challenge – it is a very significant problem.

“At the moment we estimate there is around 9,000, 7,000 to 9,000, positive cases in the country, we know who 2,000 of those are, we’ve got to hunt them down. Because that is how we get on top of the virus and lift the wider lockdown measures.”

Mr Hancock said people will not receive penalties for not abiding by the NHS test and trace self-isolation period “in the first instance”.

Pushed on people’s concerns about fraudulent NHS calls, Mr Hancock told LBC: “If anybody calls they will be calling from the number 03000135000, if you get a text it will come from NHS and they will never ask you for any form of payment or purchase or details of your bank account, and also you will then be given, if you’re online, a QR code to be able to confirm those details online.”