The return of secondary school pupils in York and North Yorkshire. after the Christmas break. will be delayed further.
Exam year students will learn remotely during the first week and then return on 11 January, with other secondary school students to follow a week later on 18 January.
Vulnerable students and those of key workers will return as planned.
All pupils will be tested too.
The majority of primary schools will open as planned on 4 January but some, in areas with the highest rates of coronavirus, will not. In an update the Government said those not reopening are all in London and the home counties.
Universities are being asked to limit the numbers of students returning in January too. A testing programme will also be in place.
Setting out a new plan in the House of Commons, Mr Williamson said schools up and down the country face a “rapidly changing situation”.
The news comes just 24 hours after the government insisted it was pushing for a full to classrooms next week.
For more on York and North Yorkshire going into Tier 3 from tonight read this story on YorkMix