Number 10 said the next steps for England should be detailed at the daily press conference, though they are dependent on further scientific advice including on the rate of transmission.
The Prime Minister has said it is his “intention” for schools to begin resuming with Reception and Years 1 and 6 from Monday, despite safety concerns from teaching unions.
But his official spokesman said the final decision before the three-week legal deadline will not be made until after ministers consider further evidence from the scientific advisory group for emergencies (Sage).
However, on Wednesday, he added: “That formal review will happen tomorrow and we are hopeful, without prejudging it, that we will be able to proceed with the reopening of schools on June 1.”
During a 99-minute interrogation by the Liaison Committee, Mr Johnson also hinted there could also be good news for restaurants and pubs, saying the government was going “as fast as we can” to reopen the hospitality industry, which he previously said he hoped to happen on July 3.
“It is very difficult to bring forward hospitality measures in a way that involves social distancing,” he told the committee. “But I’m much more optimistic about that than I was. We may be able to do things faster than I had previously thought.”
Cabinet was not expected to meet again ahead of the announcement, but the spokesman said they had already discussed the desired changes that will be introduced as long as they do not risk a spike in infections that could overwhelm the NHS.
Currently people are only allowed to meet up at a distance with one other individual from another household in a public place.
It was understood that plans to ease the social restrictions to permit people to see a greater number of their family or friends outside may be not be unveiled until after Thursday.
Downing Street insiders were suggesting the easing discussed by Cabinet Office minister Michael Gove was still dependent on the scientific advice, as was the use of private gardens for socialising.
The road map to easing the lockdown contained the possibility one household could form a social “bubble” with one other in a mutual group, but it was understood that term was being quietly dropped.
The PM has said all non-essential shops in England can reopen from June 15 after he shuttered them with the imposed the lockdown on March 23.
With deaths linked to coronavirus in the UK reaching at least 47,300, Mr Johnson has been dogged by allegations that he acted too late.
His spokesman was forced to deny that Mr Johnson had announced the schools plan on Sunday to distract from the alleged lockdown breaches by his top aide, Dominic Cummings.
Key to ensuring the restrictions can be safely relaxed is keeping down the so-called R value, the average number of people an infected individual transmits the disease to. If that figure goes above one, then Covid-19 could spread throughout society exponentially.