The mutant strain of coronavirus originated in a person from Kent, scientists believe.

Experts from New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) have revealed today that the newly discovered, faster-spreading form of the illness originated in the county.

It was previously reported that it was first recorded in the county but its origins were not clear at the time.

Its chairman, Professor Peter Horby, told the House of Commons' Science and Technology Committee it has become the most prevalent version of Covid-19 in Kent and London.

He said: "It had happened in a way which suggested it started in Kent, probably from one person, and then expanded.

"We’ve had other variants which were due to importations from overseas - but this looked like it came from a point source.

"Because it was spreading rapidly and much more rapidly than other viruses, it suggested it had a biological advantage over other viruses."

The first case of the aggressive strain was first detected on September 21 - but Nervtag and Public Health England were first made aware of it about a fortnight ago.

Epidemiologists believe that the strain could have developed in a long-term coronavirus sufferer, as this would have given the illness "a long chance to evolve over time".

Prof Horby said that scientists are now "almost certain" that the mutation is substantially more transmissible than other versions of killer bug.

Despite this, experts still do not know if there are any differences in the severity of the disease, the age distribution of cases and whether it is vaccine-resistant.

"What we’re seeing is this virus is spreading faster than other viruses, which are spreading at the same time and the same place," Prof Horby added.

"This implies there’s some kind of biological advantage to make it spread faster. At the moment, this underlying mechanism is not fully clear.

"What we don’t know yet is if there’s any difference in the severity of disease, the age distribution of cases or whether this virus is able to escape immunity induced by prior infection or vaccines.

"That’s a crucial piece of work that’s ongoing."

This comes after Boris Johnson cancelled Christmas in Kent by thrusting the county into Tier 4 over the weekend.

The Prime Minister's decision was prompted by soaring rates across the South East and the discovery of the mutated virus, which he said may be 70% more transmissible.

However, Prof Horby said the exact differences are not known yet.

The Tory leader held a meeting this morning to discuss placing more parts of the country into the strictest category by Boxing Day.

Health Secretary Matt Hancock announced on Saturday the new strain was "out of control", resulting in French president Emmanuel Macron closing the border and chaos ensuing.

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