Parents at a primary school in Bristol have been warned daily life will be 'very different' when it reopens.
And Air Balloon Hill Primary School's headteacher Tim Browse said in an email sent to parents it was 'highly unlikely' pupils would be returning on June 1.
Bristol City Council has yet to announce if it will follow suit with other authorities around the country and ignore government advice to reopen in June.
More information is expected this week from ministers about whether they still plan to allow Reception, Year 1 and Year 6 back to school after the May half term.
But bosses at Air Balloon, in St George, are already preparing parents for what to expect when pupils do return.
In an email to parents, Mr Browse said class sizes will be 'much smaller', kids may not be placed in classes with all of their friends, might not be taught by their normal teacher and there would be changes around drop-offs and collections.
"No matter how much we want everything to go back to normal, we must accept the reality of that happening is still quite far away, "said Mr Browse.
"What matters most is keeping everyone safe. That will be the most important consideration when planning for welcoming back more children to school.
"When the school is safe to open up to more children, being in school will be very different to what the children are used to experiencing.
"Class sizes will be much smaller. They may not be taught by their usual teacher. They may not be placed in a classroom with all of their friends, or, get to see them at break and lunchtimes as we will need to carefully manage our school timetable to keep everyone safe.
"There will be new rules about how to stay safe in school that take into account social distancing and effective hand sanitization.
"Even how you bring your child to school and collect them at the end of the day will likely be very different to normal."
Schools in England closed for most pupils on March 20, with only the children of key workers and vulnerable youngsters continuing to attend.
Leaders in Hartlepool, Liverpool and parts of Greater Manchester have vowed not to send their kids back to school in June.
Meanwhile, unions have slammed the plans by the Department for Education, saying teachers, pupils and their families will be at risk of catching the virus.
