The B.1.617 coronavirus variant could “pick up speed and become a big problem” in the UK as the country further eases its lockdown, an expert has warned.

The UK’s fight against coronavirus could turn bad “very, very quickly” unless the government acts cautiously on easing lockdown further, Xinhua news agency quoted Professor Tim Gowers from the University of Cambridge as saying to the Guardian on Saturday.

“So I think if that’s the way you’re going to play things, then you should be very, very cautious about every step you take… And maybe everything (will) be okay, maybe the number of people who are vaccinated will be just enough.

“But if it’s not OK, we know, because of mathematics, that things will get bad very, very quickly.

“Or at least, maybe it won’t look that quick to start with, but it’ll grow exponentially. So it’ll pick up speed and become a big problem,” he said.

Meanwhile, Professor Anthony Harnden, deputy chair of the UK’s Joint Committee on Vaccination and Immunisation (JCVI), also warned that the variant is “clearly more transmissible”.

“We need to be reassured that we’re in a very different position now in that we’ve got a highly vaccinated population and we just need to continue moving at speed,” he told the BBC on Saturday.

“We do know that with this particular variant you do need two doses to offer complete protection, and so we’re very, very keen to make sure that all those, particularly higher risk groups, that’s the over-50s and those with underlying illness, receive their second vaccination as soon as feasible.”

Meanwhile, the B.1.617 variant cases doubled in a week in England to almost 7,000, prompting concerns that the government’s lockdown roadmap will be derailed.

The roadmap is expected to see all legal limits on social contact to be removed on June 21.

It is understood that a final decision on the planed easing of lockdown will not be made until June 14.

More than 38.8 million people, or more than 70 per cent of adults in Britain, have been given the first jab of the coronavirus vaccine, according to the latest official figures.

The UK’s overall Covid-19 caseload and death toll currently stood at 4,496,823 and 128,037, respectively.