• Video report by ITV News Political Correspondent Daniel Hewitt

An NHS contact tracing app that could alert users when they have come into contact with someone who has coronavirus symptoms and should seek a Covid-19 test will be trialled on the Isle of Wight this week.

The government and the NHS's digital department, NHSX, are in the process of developing an app that would tell you if you've recently been close to someone who might have had coronavirus.

Trials will be run in the Isle of Wight this week, Transport Secretary Grant Shapps said, ahead of a potential nationwide roll out if tests prove successful.

At least half the population must use the app if it is to work, he added.

“The tracing app is one of the great things that could happen, it’s just going into trial now,” he said.

“So this is a fantastic aid to track and trace, if you like.

“It’s very important everyone in the country, everybody possible, everyone who can, downloads it because it needs to be very heavily used, perhaps 50 or 60% of the population, which will be an enormous ask.

“But it will be an NHS app and I think when we all go out there and we clap on Thursday night at 8pm, when this is available downloading the NHS app will actually be doing something practical and helpful to protect our NHS and save lives as well.”

Mr Shapps stressed the app would be completely confidential.

Amid warnings over an even more deadly second wave of infections, the transport secretary said the app is a “fantastic way” to ensure the country can “keep a lid” on coronavirus.

He he did not know how many of the 18,000 contact tracers the government is seeking have been hired.

The Welwyn Hatfield MP also admitted that fewer Britons would have died from coronavirus if more tests had been available earlier.

Speaking on BBC One's The Andrew Marr Show, Mr Shapps said “many things” could have been different if the UK’s testing capacity was above 100,000 before Covid-19 spread in the country.

More than 28,000 people have now died after testing positive for the virus in the UK.

He also warned life would not return to “business as usual” when Boris Johnson sets out his exit strategy this week.

Political Correspondent Daniel Hewitt explains how the app works

People with the app can voluntarily opt-in to record details of their symptoms when they start to feel unwell.

The app would then send an alert to other app users who were recently close to that person to let them know that they have been in contact with someone who might have coronavirus.

The app won't identify who the person is.

If that person suspected of having the virus is tested and confirmed to have it - an alert goes out warning others who were in recent contact to go into quarantine to help stop the spread of the virus.

This process is known as contact tracing.

The app uses short-range Bluetooth signals on people's phones to work out who you've been close to, storing these contacts on your phone.

Coronavirus: Everything you need to know