Nicola Sturgeon has said it is “imperative” that the Prime Minister tries to get an extension to the Brexit transition period after the discovery of a faster-spreading coronavirus strain.

Scotland’s First Minister said the UK faces a “profoundly serious situation” because of the virus mutation and warned it would be “unconscionable” to leave the European Union at the end of the year.

The Brexit transition period is due to end on December 31 but Ms Sturgeon has called for an extension amid strict new lockdown measures to try to tackle the new coronavirus strain.

She wrote on Twitter: “It’s now imperative that PM seeks an agreement to extend the Brexit transition period.

“The new Covid strain – & the various implications of it – means we face a profoundly serious situation, & it demands our 100% attention.

“It would be unconscionable to compound it with Brexit.”

On Saturday evening Ms Sturgeon said 17 cases of the new strain had been identified in Scotland – 16 of which were in the Greater Glasgow and Clyde region.

The discovery of the faster-spreading mutation prompted both the UK and Scottish governments to drastically scale back the easing of restrictions over Christmas.

Ms Sturgeon also announced all of mainland Scotland would be put under the toughest Level 4 restrictions from Boxing Day for at least three weeks.

Countries across Europe have started banning flights from Britain after the disclosure the country is the centre of the outbreak of the new variant, which is up to 70% more transmissible than the original.

France, Germany, Italy, the Netherlands, Belgium, Austria, Ireland and Bulgaria have all imposed restrictions on UK travel, while the Port of Dover announced its ferry terminal was closing to all traffic leaving the UK due to French border restrictions.

Boris Johnson is set to chair a meeting of the Government’s Cobra civil contingencies committee on Monday as ministers seek to ensure a “steady flow of freight into and out of the UK”.

The Scottish Government is expected to take part in the Cobra meeting and Ms Sturgeon will then chair a resilience committee meeting to discuss freight disruption.