The highly infectious mutant strain of coronavirus found in Kent could be more likely to affect children, scientists have warned.
Modellers at the London School of Hygiene and Tropical Medicine found the new virus strain is 56 per cent per cent more infectious.
Even if another national lockdown was implemented, it would be 'unlikely' to reduce the R to below one unless schools and universities were also closed, their study found.
But researchers do not believe the new strain is more deadly or causes any more severe disease in either adults or children.
The new coronavirus strain may be 'particularly marked' in children, scientists have warned. Pictured: Researchers at the London School of Hygiene and Tropical Medicine modelled an increased susceptibility among children to the new strain (VOC) compared to the original strain (Preexisting)
Researchers said there is 'some evidence that the increase may be particularly marked in children'.
The new variant will lead to a wave of coronavirus cases and deaths that will peak in spring 2021 for London, the South East and east of England, they said.
They said that cases and deaths will peak in summer 2021 for the rest of the country.
Schools had been due to return on January 4 but Education Secretary Gavin Williamson has ordered a week of testing and most students will return on January 11.
SAGE expert warns new mutant Covid will likely become the 'dominant global strain'
The mutated coronavirus spreading rapidly in the UK will likely become the dominant global strain, a SAGE scientist warned today as Gibraltar became the sixth place outside of Britain to detect a case of the new variant.
Calum Semple, professor of outbreak medicine at the University of Liverpool, said the new variant would 'out-compete all the other strains' because it has the evolutionary advantage of being able to spread more easily.
The strain – called VUI-202012/01 – has already been confirmed in Denmark, Gibraltar, the Netherlands, Australia and Italy, There have also been unverified reports of at least one case in Belgium.
France, and South Africa also believe they have cases of the mutation, but these have not been confirmed. French health minister Olivier Veran said it is 'entirely possible' the new variant is already circulating in France, despite tests not picking it up yet, while officials in South Africa say they've detected a strain very similar to the UK version.
Scotland and Wales have both picked up cases of the strain in recent weeks, although it is spreading predominantly in London and the South East of England, where it's thought to account for 60 per cent of all new infections.
It is now present in all parts of the UK apart from Northern Ireland, but First Minister Arlene Foster said it's 'probable' the virus is already circulating there, too.
When asked on Sky News whether the mutant coronavirus will become the dominant strain around the world, Professor Semple said: 'I suspect it will, or strains like it will.
'Because the virus has the evolutionary advantage in transmitting more quickly, it will out-compete all the other strains, and so it will naturally do that.
'As immunity comes into the community more widely, then you'll start to see more pressure on the virus and you're more likely to see other escapes of other variations.'
Only GCSE and A-level students, vulnerable children and the children of critical workers will return on time.
Coronavirus is most rampant among secondary schoolchildren, according to separate figures from the Office for National Statistics.
Those in Year 7 to Year 11 are seeing the highest rates of infection among the entire population.
Scientists hope to learn much more over the next two weeks about how quickly the variant spreads among children, Professor Neil Ferguson, an epidemiologist of Imperial College London and member of No10's advisory group NERVTAG, said.
Children have throughout the coronavirus pandemic constituted far fewer cases than for other respiratory diseases, including flu.
The leading theory for this is due to how the coronavirus enters human cells, via a receptor called ACE2 which is found on many cells in the upper respiratory tract.
As a result, Professor Wendy Barclay of Imperial College London and a NERVTAG member, explained this made adults 'easy targets' compared to children.
This is because the amount of ACE2 a person expresses naturally and steadily increases over time, with young children having very little.
'I think on the topic of children we've got to be careful about what we say. We are not saying this is a virus that specifically attacks children or is any more specific in its ability to infect children,' she said.
'But we know that SARS-CoV-2 as it emerged as a virus was not as efficient at infecting children as it was adults.
'The previous virus had a harder time binding ACE2 and getting into cells and therefore adults, which have abundant ACE2 in their nose and throat, were the easy targets and children were difficult to infect.
'The newer virus has an easier time doing that and children are therefore equally susceptible, perhaps, to this virus as adults.
'Given their mixing patterns you would expect to see more children being infected.
'It's not because the virus is specifically targeting children, but that it is now less inhibited.'
Professor Ferguson added that if this hypothesis is found to be true it may explain a 'significant proportion' of the transmission increase.
Speaking a virtual media briefing hosted by the Science Media Centre, he said: 'There is a hint that it is has a higher propensity to infect children.
'That may perhaps explain some of the differences but we haven't established any sort of causality.'
The new strain of the virus, which experts fear is more contagious, prompted more than 50 countries to impose travel restrictions on the UK, where it first emerged.
But cases of the new variant have still been reported worldwide: on Friday, Japan confirmed five infections in passengers from the UK, while cases have also been reported in Denmark, Lebanon, Germany, Australia and the Netherlands.
South Africa has detected a similar mutation in some infected people, but on Friday denied British claims its strain was more infectious or dangerous than the one originating in the UK.
The figures for December 25 are just for England, as the devolved nation's statistics haven't been included in the Government dashboard over Christmas