LONDON, May 27 — A coronavirus variant first found in India is spreading across Britain and it is too soon to say whether Covid-19 restrictions can be fully lifted on June 21, health minister Matt Hancock said today.

Prime Minister Boris Johnson has laid out a roadmap out of lockdown for England, but has warned that the rapidly spreading B.1.617.2 variant poses a risk to that plan.

"The Indian variant is spreading across the country,” Hancock told parliament. "My assessment is that it is too early now to say, yet, whether we can take the full step four (of the reopening plan) on the 21st of June.

"We will only do that if it’s safe. We will make a formal assessment, ahead of the 14th of June, as to what step we can take on the 21st.”

The B.1.617.2 variant of concern is thought to spread more rapidly than the previously dominant B.1.1.7 "Kent” variant, although vaccines still offer protection against severe disease.

On Saturday, Public Health England (PHE) said two shots of Covid-19 vaccine were almost as effective against B.1.617.2 as they were against the Kent variant, which Hancock said at the time increased his confidence that restrictions would be lifted next month.

Asked why the economy’s reopening would be jeopardised by the variant if Covid-19 vaccines still worked against it, Hancock said that not everyone had taken up vaccines they were eligible for.

Hancock also said that 10 per cent of people hospitalised with the new variant had been double vaccinated – a sign that vaccines work well, but not perfectly.

"We already knew this but we’re better able to calibrate as we see these data,” he said.

"We will learn more about this over the forthcoming week or two, before we make an assessment.” — Reuters