The former head of Ofsted believes it might be necessary to consider cancelling summer holidays and for some pupils to resit the year as a result of lost ground in schools.

Former Ofsted chief inspector Sir Michael Wilshaw also said it is time to reopen schools, but warned it is "critical" that parents are confident it is safe to do so.

Just yesterday (May 24), Boris Johnson announced that schools are still intended to reopen for Reception, Year 1 and Year 6 pupils.

Sir Michael said that parents should have “the evidence” to see how safe it will be for children to return to school.

He said: "It is all right opening up schools but if parents lack that confidence they are not going to send (children) in.

"It seems to me that the Government have got a real part to play here making sure that parents have the evidence."

The former head of Ofsted said that schools should perhaps cancel summer holidays and staff should work overtime to make up for lost time in the lockdown.

When talking about disadvantaged schools, he said: "(Schools) have really got to ensure that recovery programmes are put in place - that might mean working in holiday periods, it might mean weekend work with examinations due.

"It is a great tragedy because our education system has made huge progress in the last few years," he said.

The crisis, he said, could be averted if head teachers were committed to "recovering lost ground".

He added: "That means convincing teachers to work the extra hours, come in at weekends and holiday periods and really intensive work they do with youngsters, particularly in examination groups.”

Some headteachers in Watford have assured that children are safe, as Lara Péchard, the headteacher at St Margaret’s School in Bushey, said parents will have to “make their own choice” if they feel it is safe to bring their child back to school.

John Dibdin, the headteacher of Lanchester Community Free School, said that all schools in Watford are “on the same boat” as they have been working together to find safe methods when reopening.

Current guidance by the Department of Education says schools should limit classes to ‘social bubbles’ of 15 pupils, meaning that one group of students cannot mix or interact with other ‘bubbles’.

Some schools may have less pupils depending on how big the school is and how much staff is available.

Students will also have staggered start, break and finishing times at schools to keep children distant from one another.

There will be increased cleaning stations, limited shared items and more to ensure that children do not contract Covid-19.

Mr Johnson added that by June 15, secondary schools should provide some contact for Year 10 and 12 students.

The PM said the phased reopening of schools was "crucial" for children.

He said: "The education of children is crucial for their welfare, for their long-term future and for social justice."

“We will of course continue to consider all the evidence as we said we would do, and we will continue to work hard.”