Just as it seemed that Europe was making progress in the battle against coronavirus, a new variant has emerged which increases the risks.

Doctors have labelled the more contagious strain B117. It appears to have initially developed in London or the South of England where “cases have rocketed in the past few days,” according to the British Health Secretary, Matt Hancock.

It is not just a British problem. The European Centre for Disease Prevention has detected cases of the variant in Belgium, Denmark, and the Netherlands.

If, as feared, it is 70 percent more contagious than the previous version, it will be extremely difficult to halt its spread. Scientists say it could be almost unstoppable unless its R reproduction rate is halved.

The UK’s chief scientific adviser Sir Patrick Vallance told a televised briefing from Downing Street on Monday that the variant of the virus had to be taken “incredibly seriously.”

He warned: “You could be the person spreading it to somebody else, and you should behave accordingly.”