Boris Johnson has said it is his intention that children of all ages in England should be able to return to school on a five-day-a-week basis in September.

The Prime Minister said to “watch this space” when asked whether social distancing restrictions could be reduced from two metres to one metre to help schools in England return in autumn.

Education Secretary Gavin Williamson suggested that primary school class sizes of 15, known as “bubbles”, could be expanded back to their normal size to allow more children back in the classroom.

At the Downing Street daily briefing, Mr Williamson said he wanted all year groups to return to school “full-time” in September, adding that further guidance on safety measures will be published in the next two weeks.

“We have already been very clear that we want to see all children in all classes, returning full-time to school in September. That’s what we’re working towards,” he said.

When asked whether he had signed up to the pledge that all state school pupils will be able to go in every day, every week, not on rotation, he said: “To be absolutely clear, absolutely signed up to the fact that we want to bring every child back, in every year group, in every school.”

Speaking to broadcasters during a Hertfordshire school visit on Friday, Mr Johnson said it was “absolutely” his aspiration that pupils of all ages will be back in the classroom for a full five days a week in September.

“I want a world in which, as far as possible, provided we can make classrooms safe, and I think we can, I want every child, every pupil, every student, back in September. I’m sure we can get it done,” Mr Johnson said.

His comments came as the Government’s £1 billion plan to help pupils catch up with learning came under fire from education leaders.

Head teachers say they were not consulted on the details of the scheme, which will see the most disadvantaged children in England given access to funds to pay for tutors while the majority of the funding will be shared across schools to help pupils from all backgrounds affected by the lockdown.

College and nursery leaders have criticised the Government for leaving their pupils out after it announced that £650 million would only be given to state primary and secondary schools for the 2020-21 academic year.

A further £350 million will be spent on a one-year subsidised national tutoring programme targeted at the most disadvantaged pupils in schools.

Sector leaders say the funding will not reach young children in nurseries and college students who are most “in need of support” amid the pandemic.

It came as the UK’s chief medical officers agreed to downgrade the coronavirus alert level from four to three after a “steady” and continuing decrease in cases in all four nations.

Localised outbreaks of Covid-19 are still “likely” to occur, the advisers warned, and the virus remains in general circulation.

But the downgrading – recommended by the Joint Biosecurity Centre (JBC) – means transmission of coronavirus is no longer considered to be “high or rising exponentially”.

Mr Johnson said moving to a lower alert level would allow the Government to “start making some progress” on the current social distancing measures and promised new guidance for the hospitality sector and businesses “very shortly” – an indication that restrictions could soon be reduced.

Government scientific advisers have said they would be comfortable with a reduced distance if risk mitigating measures were taken, such as people sitting side by side and wearing face coverings.

On the school funding announcement, David Hughes, chief executive of the Association of Colleges (AoC), said it was “indefensible” to overlook the needs of students in tens of thousands of colleges across the country.

We are also concerned that there seems to be no extra financial support for early years or sixth form students – these phases are crucially important

Meanwhile, Purnima Tanuku, chief executive of National Day Nurseries Association (NDNA), has accused the Government of failing young children “who are most in need of support in their early development”.

David Laws, executive chair of the Education Policy Institute (EPI) think tank, added that the catch-up plan was “poorly targeted” and unlikely to prevent a large increase in the disadvantaged gap.

The former Liberal Democrat minister added: “We are also concerned that there seems to be no extra financial support for early years or sixth form students – these phases are crucially important yet they have suffered from persistent funding neglect over a sustained period of time.”

On the Prime Minister’s ambition to return all pupils to schools for five days a week in autumn, Geoff Barton, general secretary of the Association of School and College Leaders (ASCL), said schools and colleges were trying to prepare for September amid an “information black hole” from the Government.

Mr Barton said school and college leaders are preparing for two scenarios for the autumn – using rotas to stagger the return of pupils or bringing students back full-time – amid an “absence of information”.

Paul Whiteman, general secretary of school leaders’ union NAHT, said: “The desire to bring everyone back is correct but we need to know what the Government is thinking and the scenarios they are planning for.

“This will give school communities what they need to get through this term and plan for the new academic year in September.”

Kevin Courtney, joint general secretary of the National Education Union (NEU), added: “The Prime Minister’s hopes are not enough.”

“If the requirements of social distancing – in order to stop a second peak – are reduced even to 1m, then most schools could not have 30 children in a classroom,” he added.

Speaking on Sky News, Mr Gibb said: “We are working with the school sector, we’re taking advice and we give schools plenty of notice in time to plan for that reopening in September.

“Of course, we’re working on other contingency plans but the clear intention is that we’ll have all children back in school in September.”

Mr Gibb said the catch-up funding for schools will begin to be distributed from the start of the academic year in September – and head teachers will have the discretion to decide on how the funding is spent.

In Northern Ireland, most pupils are set for a return to education in the autumn after ministers agreed to cut the social distancing measure to one metre.

When asked on Friday whether this could happen in schools in England, the Prime Minister said: “Of course, on the social distancing measures, as I’ve said, watch this space. We will be putting in further changes as the science allows.”

New figures published by the Government show the rate of spread of the coronavirus infection across the UK is shrinking.

For the UK as a whole, the current growth rate is minus 4% to minus 2% and the estimate of the reproduction number, referred to as R, remains at 0.7 to 0.9.