The government review on whether to end social distancing restrictions could be delayed beyond the end of the month due, to concerns about the Covid variant that originated in India.

Downing Street said on Monday that Boris Johnson still wants to complete the review “as soon as possible” but that ministers “need time to assess the latest data” on the variant.

The prime minister last week suggested the one metre-plus rule could be scrapped along with other social restrictions on June 21, the earliest date stage four of the lockdown lifting can go ahead.

Johnson also said “you’ll hear a lot more by the end of this month” on whether social distancing could be scrapped, adding that he felt “very positive”.

But the mood had dimmed by Friday, when the PM admitted that the June 21 opening up is now in doubt due to the possible increased transmissibility of the Indian variant.

And his official spokesperson confirmed that the review on whether social distancing will need to stay in place even after Jun could now be delayed by the end of the month.

The spokesperson told reporters: “We want to do it as soon as possible but as I have set out we need time to assess the latest data on this variant first identified in India, so I am not going to give a set time for doing that.

“Like you say, given this change in circumstance. But we want to do everything possible to give people enough time to prepare.”

Asked if the commitment to carry out the review by the end of the month no longer holds, they replied: “That’s correct.”

From today people in England can meet outdoors in groups of up to 30, and indoors in groups of six, or two households, with pubs and restaurants able to serve customers inside. Museums, cinemas and other indoor attractions can reopen.

The “stay in the UK” restriction has also lifted and people will be able to go on holiday to “green list” countries including Portugal without having to quarantine on their return, provided they take one post-arrival test.