From the Guardian:
"Boris Johnson has announced that he hopes to begin reopening England’s schools from Monday 8 March, with the date to be confirmed next month.
The prime minister said a firm decision would be taken in the week of 22 February, after the spring half-term – the date by which he had originally hoped schools would reopen.
He said by then the government would have a clearer picture of how the vaccines are helping to contain transmission of the virus, and cut hospital admissions."
Key phrase, "hopes to begin re-opening schools"
A lot will depend on the vaccine, hospital admissions, etc.
I take it as this is the earliest date that they might start to re-open schools if all goes well.
And I really hope it's a phased return, with extra measures in place for staff and students.
Otherwise we'll be in a perpetual cycle of lockdowns.