Coronavirus “mutations of concern” have been detected in Liverpool and Bristol, Matt Hancock has said.

Around 80,000 people in England are already set to receive door-to-door Covid testing after the discovery of 11 cases of the South African coronavirus variant in people who hadn’t travelled to the country.

The surge testing provided by mobile laboratories and local public health staff will cover eight different local areas covering parts of London, Walsall, Broxbourne, Maidstone, Woking and Southport.

Speaking in the Commons on Tuesday, Hancock added: “We have also seen 11 cases of mutations of concern in Bristol and 32 in Liverpool, and are taking the same approach.

“In all these areas it is imperative that people must stay at home and only leave home where it is absolutely essential.”

The health secretary said: “We must continue to act with caution, not least because of the renewed challenges posed by new variants of the coronavirus.”

The government is under fire for its decision not to impose stricter measures on people arriving into the UK. 

A new rule requiring travellers returning to the UK from some coronavirus hotspots to quarantine in government-secured hotels is set to come into force. But the government has yet to announce when it will be in place.

Boris Johnson has also decided to limit mandatory hotel quarantine to arrivals from a list of 30 “high-risk” countries including Portugal, South Africa and parts of South America.

Labour attacked the move as “half-baked”, for leaving “gaping holes” at the border through which new variants of coronavirus could be imported. 

And according to The Times, the Scientific Advisory Group for Emergencies (Sage) warned Boris Johnson “geographically targeted travel bans” would not be enough.

Instead, the scientists said, mandatory quarantine measures were needed for everyone entering the UK.