Genomic researchers have found the new and more infectious variant of Covid-19 has already spread around the UK, with cases identified in Wales and Scotland.

The Covid-19 Genomics UK (COG-UK) consortium sampled cases around the UK and found the variant is also in the South West, Midlands and North of England – areas that are under Tier 2 and 3 restrictions.

Scientists Professor Lawrence Young and Professor Robert Dingwall explained the new variant is more transmissible because it “sticks” more easily to receptors in the throat and nose – which preliminary research also suggests is the reason it seems to be more prevalent among children.

Prof Dingwall, who is a leading medical sociologist and sits in committee meetings with Nervtag virologists every week, said: “My understanding of it is that you are producing more of the infection in the upper respiratory tract and the virus is reproducing faster so that there is more to go into the air, to pass from one person to another.”

Prof Young, a virologist at Warwick Medical School, added that children have less of the receptors which picked up the older coronavirus variant, meaning they were less likely to catch it, but the new variant “might compensate for lower levels of that receptor or that door to the virus in children by being stickier”.

Health chiefs in Cumbria have said the new variant is in the county and could be behind some sharp increases in new cases.

Director of public health for Cumbria Colin Cox said in the district of Eden rates had risen to 345 cases per 100,000 people, the highest seen in Cumbria to date, and Lancashire’s director of public health Sakthi Karunanithi said there was a “high likelihood” the new variant was in the county.

Greater Manchester mayor Andy Burnham said there was no evidence the strain has reached the area but what public health directors “want to emphasise is it is safe for people to assume that it is already here or it is about to arrive”.

On Monday, Brighton’s council leader Phelim Mac Cafferty said the number of cases in the city had “more than doubled in one week”.

It is certainly not isolated in one place, it has begun to spread to many places in England

Jeffrey Barrett, lead Covid-19 statistical geneticist at COG-UK, warned there was a lag in the sequence data being sampled, so the most recent data was from the first week of December when England came out of the second national lockdown.

The new variant led to London and parts of southern and eastern England being rushed into the new Tier 4 regime at the weekend, effectively cancelling Christmas plans and imposing measures similar to previous national lockdowns.

Dr Barrett said more up-to-date data from community testing also found one of the mutations of this variant is “present in very many different places in England”, and Professor Tom Connor, a genomics expert from Cardiff University, said this was the same for Scotland, and Wales – which has sequenced more viruses in the past week than the whole of France since March.

Prof Connor said it was no surprise that a new variant had been found in countries – including the UK, Denmark and the Netherlands – which have mature sequencing systems set up, and he believed similar variants will pop up around the world.

Ravindra Gupta, professor of clinical microbiology at the University of Cambridge, told the briefing that a new variant had also been detected in South Africa, which also does a lot of sequencing.

The new variants found in the UK, South Africa, Denmark and the Netherlands led to Germany banning travel from those countries.

Sharon Peacock, director of COG-UK and a professor of public health and microbiology at the University of Cambridge said there was no evidence to suggest the new variant caused higher mortality, and no reason to believe the vaccine being rolled out in the UK will not be effective.

However, Prof Connor warned not enough time has passed to know whether the variant leads to a worse outcome for infected people.

He said: “When you’re talking about outcome you’re normally looking at 28 days after the person has been diagnosed – with a lot of these cases popping up in late December we’re not at that point where you would have that outcome information to do that analysis yet.”

Dr Barrett said 23 mutations of the virus were detected “all at once”, which is rare, suggesting it did not happen by coincidence.

He said: “It suggests that something happened – we don’t know what that something is, that produced this variant, and it doesn’t happen that often because we haven’t seen it before.

“I think the conjunction of very rapid spread and a lot of mutations makes this less and less likely to be just a coincidence.”