India has been added to the coronavirus “red list” in response to mounting concern about the number of cases there and the emergence of a variant.

The move, announced just hours after Boris Johnson was forced to cancel a trip to the country, comes into force at 4am on Friday, meaning Britons returning after that point will be forced to quarantine in a hotel for 10 days.

Anyone who is not a UK or Irish resident or a British citizen will be banned from entering the country if they have been in India in the previous 10 days.

Health Secretary Matt Hancock said so far 103 cases of the Indian variant had been identified in the UK.

Concern about variants of the disease – and whether existing vaccines will prove effective – has led to the Government ramping up plans for a campaign of booster shots later this year.

Mr Hancock told MPs: “We’ve recently seen a new variant first identified in India. We’ve now detected 103 cases of this variant, of which again the vast majority have links to international travel and have been picked up by our testing at the border.”

Mr Hancock said the samples have been analysed to see if the new variant has any “concerning characteristics” such as greater transmissibility or resistance to treatments and vaccines.

He added: “After studying the data, and on a precautionary basis, we’ve made the difficult but vital decision to add India to the red list.”

The health secretary also confirmed that surge testing will be rolled out to curb the spread of the Indian variant.

Labour’s Jonathan Ashworth said: “As of today, UK COG (Covid Genomics UK) reports 135 cases of B1617 in the UK, 115 in the last 28 days – the fastest growing variant in the UK in the last three weeks.”

Mr Ashworth said his party “welcome” the move to place India on the red list, adding: “But we also now have cases in the community not linked to international travel.

“Now I understand that (Mr Hancock) is carrying out analysis of those samples. But surely we now need to start surge testing and designate the B1617 as a variant of concern.”

Discussing India being added to the red list, Mr Hancock said: “This isn’t a decision which we take lightly.

“(Mr Ashworth) is right to ask about surge testing to make sure that we limit the spread as much as is possible of the variant first found in India – and we will be doing that, I can confirm.”