Teacher assessments will replace GCSE and A-level exams in England this summer, the education secretary has announced.

Gavin Williamson set out his plans for students as MPs prepared to vote on England's latest lockdown, with the government under pressure over the schools' chaos and its strategy for deploying Covid-19 vaccines.

He told MPs "schools have not suddenly become unsafe".

"The last thing any education secretary wants to do is announce that schools will close, and this is not a decision that the Government ever wanted to take," he said in a statement.

"I'd like to reassure everyone that our schools have not suddenly become unsafe, but limiting the number of people who attend them is essential when the Covid rates are climbing as they are now.

He said it was necessary to curb the escalating Covid-19 cases throughout the country to "prevent the NHS from being overwhelmed".

Boris Johnson said on Wednesday the lifting of restrictions would be a "gradual process" and not a "big bang" - and that schools would be "the very first things to reopen".

"That moment may come after the February half-term, although we should remain extremely cautious about the timetable ahead," the prime minister told MPs.

Education Select Committee chairman Robert Halfon earlier told Sky News the situation regarding schools was "a mess".

"I think now we have to move on and make sure we have an exam system that is a level playing field for students and fair to the disadvantaged," he said.

The Commons has been recalled from its Christmas recess to debate and retrospectively vote on the latest England lockdown set by Prime Minister Boris Johnson on Monday.

The other three nations are taking a similar approach, with First Minister Nicola Sturgeon imposing a lockdown on Scotland for the rest of January and the closure of schools until February.

Schools and colleges will be closed in Wales until at least 18 January and move to online learning, with GCSE and A-level exams already cancelled.

In Northern Ireland, pupils will learn remotely until the mid-term break but it is unclear whether exams will go ahead.