The government’s test, track and trace system will be in place by June 1, Boris Johnson has said.

Government scientists said yesterday that reopening schools was reliant on such a system being in place, following reports the scheme was delayed.

Asked by opposition leader Sir Keir Starmer if the system would be in place by June 1, Johnson said: “We have a growing confidence that we will have a test, track and trace operation that will be world-beating, and yes, it will be in place, it will be in place by June 1.”

The government’s deputy chief scientific adviser Dame Angela McLean revealed yesterday that government scientists “have been clear in our advice that changes to lockdown as we modelled them need a highly effective track, trace and isolate system to be in place”.

Therese Coffey, the work and pensions secretary, told BBC Breakfast yesterday morning that the government’s contact tracing app, currently on trial on the Isle of Wight, would be ready for rollout in the “coming weeks”. But she claimed she was “not aware that’s been set as a condition that’s necessary for the phased reopening of primary schools”.

During PMQs, Starmer asked for assurances about the system given that “there now appears to be some doubt as to when this is actually going to be ready”.

But Johnson insisted it would, adding that there would be “25,000 trackers, they will be able to cope with 10,000 new cases a day”.

“That’s very important, because currently new cases are running at about 2,500 a day. They’ll be able to trace the contacts of those cases and to stop the disease spreading.”

Unions have also demanded a national track and trace system needs to be in place before schools reopen.