Eighteen English councils have expressed concern over the government's policy of lifting lockdown at centres of education.
As many as 1,500 primary schools could defy government recommendations as local bodies query the decision to loosen lockdown measures for primary schools during the coronavirus epidemic.
The government has come under increasing pressure in recent days over the decision with teachers, parents, unions and councils questioning the reopening date.
Some have urged the government to reconsider the move, with Patrick Roach, general secretary of the NASUWT saying that he remained unconvinced that a move was either "appropriate or practicable".
Concerns over a sufficient supply of PPE for teachers is among many fears being raised by affected stakeholders.
Parents now face confusion over whether there child's school will be reopened by June or not.
What is the government's plan for schools in England?
Speaking at a public address on May 10 Mr Johnson said that "At the earliest by June 1, after half term, we believe we may be in a position to begin the phased reopening of shops and to get primary pupils back into schools, in stages.”
Mr Johnson said that children in Reception, Year 1 and Year 6 would be the first to be welcomed back, if infection rates were to drop a significant amount and if the government’s five tests were met.
Secondary school are likely to be closed until September, however according to the latest plans from the Westminster Government.
Mr Johnson said: "If we can't do it by those dates, and if the alert level won't allow it, we will simply wait and go on until we have got it right.”
"If there are problems we will not hesitate to put on the brakes."
On May 20 Number 10 said the government remain committed to more children returning to school "as soon as we can".
The PM's spokesman said: "The Department for Education continues to meet with head teachers, teachers and the unions, and we continue to listen to their concerns.
"We have a plan for a cautious phased opening from June 1 and we do want to get more children back into school as soon as we can, but when it's safe."
The Prime Minister said that to support social distancing class sizes would be limited to 15, with staggered break times and frequent hand washing also necessary.
And which councils have said they won't reopen?
Calderdale, Liverpool, Bury and Hartlepool councils have all advised against the reopening of schools on June 1.
Several other local authorities have expressed concern.
Solihull Council, a Conservative-led authority, warned that some schools may not be ready for early June.
Manchester City council meanwhile have said that schools in the area would need to work at their own pace.
Birmingham City Council have also said that it may not be possible to open up all primary schools in line with the government's ambitious aim.
In Yorkshire, Leeds City council have said it would be unrealistic to open up all primary school in the city "from day one".
Stockport Council have said that schools in the area would not open until June 10 at the earliest.
Slough authorities have said that schools would not open in the area until June 8 at the earliest.
Brighton and Hove City council have advised for primary schools only to open when a risk assessment suggested it was "safe to do so".
In Bradford Councillor Imran Khan, said: “Bradford council has no intention of directing schools to open on 1 June".
Many other concerns have expressed concern over safety, but have not yet advised schools to reject the government timeline.
Why are schools refusing to reopen?
a poll from teachers' union NASUWT suggested that only 5% of teachers think it will be safe for more pupils to return to school next month.
In a letter to the Education Secretary, Patrick Roach, general secretary of the NASUWT, said the union remains "unconvinced" that wider reopening of schools from June 1 is "appropriate or practicable".
The survey, of nearly 29,000 NASUWT members across England, found that around nine in 10 teachers believe that social distancing will be impossible, or will present major issues and a similar proportion are not confident that the proposed measures will protect their health or the health of pupils.
It also found that 87% of teachers believe that PPE is essential to protect staff against the virus.
Dr Roach said: "The results of our survey underscore the fact that the Government has thus far failed to win the trust and confidence of teachers about the safety of reopening schools.
"It is now imperative that the Government takes every available opportunity to provide the necessary assurances that teachers are seeking."