Will schools be closed next term by variant of virus?

Like those lorries stuck in Kent, the new variant of coronavirus is putting plans for reopening schools next term in a holding position.

There's a cloud of uncertainty hanging over whether schools in England will really begin to return from 4 January - and whether the plan will stay in place for a staggered start with some secondary pupils returning on 11 January.

Asked for a guarantee on whether schools would go back as planned, the Prime Minister Boris Johnson said "the commonsensical thing to do is to follow the path of the epidemic".

The government would "keep things under constant review", he said.

It sounded more like let's wait and see, rather than full steam ahead.

The official line from the Department for Education is that the existing plans and new year timetables are still in place - and that it remains a priority to keep schools open.

But a statement on Tuesday comes with the rider, or maybe a get-out clause, that "the path of the pandemic is changing".

This new variant virus and the pre-Christmas clampdown seems to have knocked the wind out of the sails of many of us.

And for those planning the return of schools in less than two weeks' time it's added even more pressure.

Head teachers' leader Geoff Barton said that in such a "fast moving and developing situation" the government must not "rigidly stick to its plan come what may".

If the new variant spreads more easily among young people, should they be kept out of its path? And does that mean delaying the start of school next term?

At present the plan is for primary schools and secondary school exam years to go back on 4 January - and the rest of secondary pupils to return on 11 January.

But the risk of the new mutant variant could see that timetable overtaken by events - and ministers will be expected to be as fleet-footed as this accelerating strain of the virus.

If the tightening restrictions mean it's no longer safe for a family to travel to meet together at Christmas, is it tenable to send children and teachers to gather in large numbers inside school?

And if the virus does move rapidly through this age group, would schools end up being closed by default, with so many pupils having to be sent home?

The biggest teachers' union, the National Education Union, has called for the first two weeks of term to go online, allowing all pupils to be tested before returning to the classroom.

And there have been reports of even longer delays to the new term being considered.

Every action has a reaction - and keeping pupils off school would also have consequences, apart from the political pitfall for the government of being accused of a U-turn.

Working parents will worry about finding childcare, particularly at short notice, and might not be too delighted at the prospect of home schooling again.

There will be questions about falling behind in learning and concerns about children's well-being - with Ofsted having flagged up a legacy of problems from the first lockdown.

This wasn't only slipping back in academic terms, but inspectors have warned of young children losing "basic skills" such as using a knife and fork.

Many families do not have the computer kit at home for online study, and the "digital divide" would get even wider.

If any more teaching time is lost, there will be arguments over how exams can go ahead in the summer in a way that's fair.

The January return to school was also going to mark the start of mass Covid testing for secondary schools - a key part of the plan to end the cycle of schools having to send home so many pupils every time they had a Covid case.

That testing plan had become highly contentious, with school leaders furious about a lack of notice and warnings that it could not be set up in time.

But any decision on postponing the start of term would also have a knock-on effect for the start of testing.

If there are some win-win decisions in politics, this is closer to the lose-lose end of the spectrum.

Time is ticking away - and with the Christmas holidays there are only five working days before schools are meant to return.

Will the evidence on the new variant virus really be available in time to make an informed decision on reopening? And in the absence of certainty, what will ministers' New Year's resolution be for schools?