The NHS Covid-19 contact tracing app utilized in England and Wales could be made less sensitive in order to decrease the number of people asked to self-isolate.

The app detects the distance between users and the length of time spent in close proximity – currently 2m or less and more than 15 minutes.

A source close to Health Secretary Sajid Javid said he was considering changes, amid a huge rise in alerts.

The Department of Health said the app “is, and always has been advisory”.

The system allows people who test positive to anonymously share their test result, triggering alerts for those detected as close contacts in the days before the test.

Under current rules, those who receive an alert are asked to stay at home for up to 10 days.

The hospitality industry and NHS trusts have warned MPs that the knock-on effect for the economy and workplaces could be huge, as it could lead to millions being asked to self-isolate this summer.