Ministers are due to decide whether to move more areas of England under the toughest restrictions amid concern over spreading of a new variant of Covid-19.

Cabinet minister Robert Jenrick said No 10 would make a "judgment" on whether the tiers system was "strong enough".

Ministers to decide on extension of tier 4 restrictions to more areas https://t.co/Q5WmS7Sj8b

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He said there was no "immediate plan" to widen curbs on Boxing Day but "the number of cases is rising".

The UK's chief scientific adviser Sir Patrick Vallance has said extra curbs could be needed in more areas.

He told a Downing Street briefing on Monday that measures could "need to be increased in some places, in due course, not reduced".

Mr Jenrick told BBC Breakfast that the Covid operations committee, chaired by Prime Minister Boris Johnson, will meet on Wednesday morning to discuss the tier system.

He said they were "trying to retain the robust tiered system" which takes a "proportionate approach" across the country, but said it had been designed before the new variant became apparent which is a "game changer".

He said the new variant - which could be up to 70% more transmissible - was now present in other areas of the country, albeit to a "lesser extent" than in London, south-east and the east of England.

He said: "The variant is spreading to other parts of the country, so we will see whether it's necessary to do more and make sure that the tiered system is sufficiently robust for the new circumstances.

"The tiered system was designed before we knew the full ferocity of the new variant, and so we do have to make sure it's sufficiently robust to be able to withstand this and to stop cases just rising at the very worrying levels they are now in parts of the country."

On Tuesday, a further 36,804 people in the UK tested positive for the virus and there were 691 deaths within 28 days of a positive test, according to government figures.

It is the largest daily number of cases recorded yet, though it is thought the infection rate was higher during the first peak in spring when testing was much more limited.