A testing and tracing system seen as the key to easing the lockdown will be up and running by June 1, Boris Johnson has promised, but the rollout of the contact tracing app will come later.

The Prime Minister said 25,000 staff would be in place by the start of next month – the earliest possible date earmarked for the gradual reopening of schools and shops in England – and they would be capable of tracking the contacts of up to 10,000 new Covid-19 cases a day.

His comments came after Cabinet minister Robert Buckland conceded there may not be a “uniform approach” to reopening England’s schools in the face of opposition from councils and unions.

The Government’s deputy chief scientific adviser Professor Dame Angela McLean has said that the modelling for changes to the lockdown were based on a “highly effective track, trace and isolate system” being in place.

At Prime Minister’s Questions Mr Johnson said: “We’re making fast progress in testing and tracing and I have great confidence that by June 1 we will have a system that will enable us, that will help us very greatly to defeat this disease and move the country forward.”

The capacity to trace the contacts of 10,000 people far exceeds current levels of confirmed Covid-19 cases.

Widespread contact tracing was abandoned in mid-March as the number of cases soared in the UK.

Health Secretary Matt Hancock said last week that the contact tracing app – part of test, track and trace – would be rolled out across England from mid-May but that has now been pushed back.

Mr Johnson did not mention the app – currently being trialled on the Isle of Wight – as part of his plan for June 1.

Downing Street later confirmed that the app would be rolled out “in the coming weeks” – after human contact tracing.

The Prime Minister’s official spokesman told a Westminster briefing the app “is only one part of the system” and that there is a “tried and tested” system for tracing and testing people.

Asked earlier if schools reopening depends on test, track and trace being fully in place, Mr Buckland told BBC Radio 4’s Today programme: “I think the position is somewhat more nuanced than that.”

Ministers are facing pressure from several councils and teaching unions to reconsider plans to reopen English primary schools.

At the moment, Reception, Year 1 and Year 6 are due to go back from June 1 at the earliest, with other years phased in before the summer break.

Mr Buckland said Number 10 is taking all concerns “very seriously”.

He told BBC Breakfast: “I don’t think any of us want to put either children or our dedicated teaching staff in any danger at all, and the question of being safe is clearly paramount.

“So we’re all working towards June 1 and planning for that return, but I accept the point that there may well be issues from employers that need to be addressed which might not mean we’ll see a uniform approach on June 1.”

Mr Buckland acknowledged that the test and trace system “won’t necessarily be as widespread and as full-blown as we would like” when it is launched.

Elsewhere:

– Captain Sir Tom Moore, who raised more than £32 million for the NHS, said he is looking forward to being knighted by the Queen and joked that he hoped she would not be “heavy-handed with the sword as by then I might be rather a poor old weak soul”.

– The Prime Minister said the deaths of 181 NHS staff and 131 social care workers have been reported as involving Covid-19.

– Mr Johnson said “no one was discharged into a care home this year without the express authorisation of a clinician” as Labour leader Sir Keir Starmer again challenged him on the crisis in care homes.

– The British Medical Association (BMA) said schools should reopen “as soon as it is safe to do so” though it said there is “no united view yet” on whether children can spread coronavirus.

– Rolls-Royce, which makes plane engines, said it will cut 9,000 jobs as it warned it will take “several years” for the airline industry to recover from the Covid-19 pandemic.

– Nazanin Zaghari-Ratcliffe’s temporary release from a Tehran prison during the pandemic has been extended again, according to her MP.

Meanwhile outsourcing giant Serco, which is responsible for recruiting and training the new contact tracers, was forced to apologise after accidentally sharing the personal email addresses of almost 300 people involved in the scheme.

Mr Buckland said the firm had “rightly” apologised for the mistake, adding: “It brings into stark relief the importance about privacy, about confidentiality, which underpins all of this.”

The Cabinet minister was also asked on Wednesday about new slogans being used by the Government instead of the “Stay Alert” message, which has been criticised for being too vague.

The slogan “Keep our distance, wash our hands, think of others, play our part” has been used in recent days.

Asked about the change, Mr Buckland told Sky News that Stay Alert is “more difficult” to explain than Stay At Home because it involves “more nuanced messages”.

He said: “It is going to be a tough ask; it is a very difficult time for everybody and the Government doesn’t pretend anything otherwise.

“We have to keep developing those messages and that’s why you’re hearing that kind of detail.”