Teachers' estimated grades will be used to replace cancelled GCSEs and A-levels in England, says Education Secretary Gavin Williamson.

He told MPs he would "trust in teachers rather than algorithms", a reference to problems in last year's exam results.

The Ofqual exam watchdog will now have to devise how this will work.

Teachers' grades will replace exams in England https://t.co/r1LzpiMvZ3

— BBC Education (@bbceducation) January 6, 2021

Mr Williamson also said it would be "mandatory" for schools to provide "high-quality remote education" of three to five hours per day.

He said Ofsted inspectors would check that this was delivered.

Labour's Shadow Education Secretary, Kate Green, accused Mr Williamson of "chaos and confusion" - and said he had failed to listen to the teaching profession.

Geoff Barton, leader of the ASCL head teachers' union, said there were "no easy answers" in picking an approach to replacing exams - but it had to avoid repeating the "shambles" of last summer's cancelled exam season.

He said there was a "real need for urgency" to allow schools time to plan - and that any system for grading had to show "fairness and consistency".

Written papers for GCSEs and A-levels are not going ahead - after this week's decision that it was no longer feasible with so much time lost in the Covid pandemic and the latest lockdown.

Mr Williamson has told the exams watchdog to come up with proposals for an alternative way of deciding results, which could be used for jobs, staying on in school or university places.

Last year's attempts to find an alternative approach to exam results, which initially used an algorithm, descended into chaos - and eventually switched to using teachers' grades.

And without any exam papers or standardised mock exams, the use of teachers' grades, with some process of moderation, will be used for this summer's candidates.

Vocational exams, such as BTecs, are carrying on, if schools and colleges decide to continue with them.

But if students cannot take BTec exams this month as planned, they will be able to take them at a later date or otherwise still be awarded a grade, if they have "enough evidence to receive a certificate that they need for progression", says the awarding body Pearson.

An Ofqual spokeswoman said they could consider options for replacement exam results, academic and vocational, "to ensure the fairest possible outcome in the circumstances".

Although the process is only formally beginning, with a consultation likely on proposals, it is understood that contingency planning had already started to find a back-up if exams were cancelled.

The exams watchdog's decisions will face much scrutiny - with the previous head of Ofqual resigning after last summer's U-turns over grades.

"We are discussing alternative arrangements with the Department for Education. We know that many are seeking clarity as soon as possible," said Simon Lebus, Ofqual's interim chief regulator.