The spread of the Indian variant has thrown the timings of key coronavirus announcements into doubt.
Boris Johnson said last week that the government would be “saying more later this month about exactly what the world will look like” on 21 June and “what role there could be – if any – for certification [having to prove your COVID status] and social distancing”.
The prime minister also told MPs that ministers would “before the end of this month, set out all the details about the marriage world post-21 June”.
That date is when the government hopes to lift all legal limits on social contact under step four of its roadmap for easing coronavirus restrictions in England.
But asked about these announcements on Monday, Mr Johnson’s spokesman did not commit to the previously suggested timetables.
“We need time to assess the latest data on this variant first identified in India so I’m not going to give a set time for doing that,” he said when asked about the review into COVID certification.
“We want to do everything possible to give people enough time to prepare. The change in circumstance means we can’t guarantee it by the end of this month.
Asked about an announcement on social distancing, the spokesman said: “Our aim is to give the public as much information as possible at each step.
“As the prime minister has said, disruption is possible because of the Indian variant. Our decision will be based on the latest data, which we will set out as soon as the data allows.”
And on weddings, he said the “new threat” from the variant means ministers “need to look at data”, adding that “we want to give businesses and individuals as much time as possible to prepare”.
Health Secretary Matt Hancock told MPs on Monday there are now more than 2,300 cases of the variant in the UK, with 86 local authority areas reporting five or more cases.
The spread of the variant – which scientists fear could be up to 50% more transmissible than the Kent variant – has raised questions about the fourth step in the government’s plan for lifting restrictions.
“I have to level with you that this new variant could pose a serious disruption to our progress and could make it more difficult to move to step four in June,” the PM told a Downing Street news conference on Friday.
But the roadmap being knocked off course is far from certain at this stage.
Mr Hancock told the Commons that early data indicates current vaccines are effective against the Indian variant.
But he said the evidence of its increased transmissibility “poses a real risk”.
One of his cabinet colleagues, Business Secretary Kwasi Kwarteng, told Sky News on Monday it was “very likely” that step four will be able to go ahead as planned.
The PM’s spokesman said: “The PM set out the position last week, you know we are proceeding cautiously, we will keep a close eye on the data and as the business secretary made clear this morning currently there’s nothing in the data to suggest we can’t proceed.
“But obviously we are keeping a very watchful eye on the outbreaks of the variant first identified in India, and particularly what impact it has on hospitalisation rates, and things like that.”