The prime minister has announced the government’s intention to open primary schools in England more widely from next Monday, while also “providing some contact” for secondary school students from June 15.

Boris Johnson was speaking at a press conference in Downing Street when he said the phased reopening of schools was “crucial” for children.

He said: “Today, I can announce it is our intention to go ahead with that as planned on June 1, a week on Monday.

“We then intend from June 15 for secondary schools to provide some contact for year 10 and year 12 students to help them to prepare for exams next year, with up to a quarter of these students in at any point.”

The prime minister said his government wants to get children back into classrooms in a “manageable and safe” way.

“The education of children is crucial for their welfare, for their long-term future and for social justice,” he said.

“In line with the approach being taken in many other countries, we want to start getting our children back into the classroom in a way that is as manageable and as safe as possible.

“We said we would begin with early years’ settings and reception, year one, and year six in primary schools.”

Mr Johnson added: “By opening schools to more pupils in this limited way we are taking a deliberately cautious approach and this comes after a constructive period of consultation with school teachers and unions.

“The Department for Education will engage with teaching unions, local authorities and school leaders in the coming days giving them an opportunity to ask questions and probe the evidence behind our plans.

“The final decision will be taken as part of the formal review into lockdown measures which the law requires us to undertake by Thursday.”

The prime minister acknowledged it would be “tough” to reopen schools but promised to work with councils on the plan for England.

“This is going to be tough,” he told the Downing Street press conference as he thanked teachers and staff who had worked to keep schools operating for the children of key workers and for vulnerable pupils.

“What we will do is make sure that we stagger things and we pace things and we work directly with you, with local authorities, to make sure that there is a plan.”

He said the key to fully reopening schools by September “at the very latest” is to “keep pushing down” the coronavirus R value – the rate at which the disease is transmitted.

“That is going to be the most effective way to ensure that not just our schools but all our economy is ready to go back as fast as possible,” he said.

“I acknowledge that the June 1 opening may not be possible for all schools but the Government will continue to support and work with the sector so that any schools experiencing difficulties are able to open more widely as soon as possible.”

Mr Johnson said the government would set out what stage two of the coronavirus recovery strategy means for other areas, such as non-essential retail and more social contacts, “over the course of the next week”.

He said: “We are making good progress, but that progress is conditional, provisional.

“We must keep reducing the incidence of this disease, we must keep that R down below 1 and that means we must all remember the basics: wash our hands, keep social distance, isolate if you have symptoms, get a test.

“We are beating this thing, but we will beat it all the faster if we stay alert, control the virus and save lives.”

Dr Patrick Roach, general secretary of teachers’ union NASUWT, said: “The Prime Minister’s display of determination to press ahead with the wider reopening of schools from June 1 is seriously at odds with the scientific evidence released to date, and the deep concerns expressed by schools, teachers and parents.

“The Government has yet to reassure parents and teachers that opening schools from June 1 will be safe and now appears to accept that many schools will not be able to reopen on that date.

“The Government has to recognise that it has not won the trust and confidence of the teaching profession.

“Notwithstanding the Government’s assertions, the bottom line is that no teacher or child should be expected to go into schools until it can be demonstrated that it is safe for them to do so.”

Kevin Courtney, joint general secretary of the National Education Union, disagreed with the June 1 date for reopening England’s primary schools.

He said: “The NEU does not agree that it would be right for primary schools to open more widely on June 1.

“We once again call on the Government to engage meaningfully with the education unions on these matters.

“We stand ready to talk to the Government about how our five tests can be met and then how we can then proceed to a safe wider re-opening of schools.”

Liberal Democrat education spokeswoman Layla Moran said: “Parents, children and teaching staff are worried about the threat of coronavirus and need reassurances ahead of reopening schools.

“Despite the concerns, the Prime Minister seems intent on rushing to bring schools back in a bid to distract from his scandal-hit spin doctor-in-chief.

“The concession to give some secondary school children contact with their teachers from June 15 also highlights the failure to push down the R number. The public deserve answers.”