Boris Johnson has reversed a decision to relax a range of lockdown restrictions due to come into force on Saturday, which would have included the reopening of leisure businesses such as casinos and bowling alleys, and allowing beauty salons to carry out close-up treatments.

Speaking at a hastily arranging Downing Street press conference, the prime minister said it was time to “squeeze that brake pedal in order to keep that virus under control”. The postponement of the new freedoms will be delayed until at least 15 August.

Rules on face coverings would also be extended from 8 August, meaning people would be obliged to also wear them in indoor venues such as museums, galleries and cinemas, Johnson said. The decision to allow weddings to have up to 30 guests is also being reversed.

The announcements come hours after the government imposed new restrictions on more than 4 million people across northern England. “I’m really, really sorry about that, but we just cannot take the risk,” Johnson said about the impact on businesses and families.

However, guidance that employers should allow more staff to begin working from offices again will still be in place from Saturday, part of a government push to get the daytime commuter economy moving again.

Johnson said that since he gave a press conference in mid-July about the gradual easing of rules, “in many ways that progress continues”, such as falling numbers of hospital patients. But he added: “I have also continually warned that this crisis could come back and we would not hesitate to take swift and decisive action as required.”

Citing new statistics showing a rising national incidence in Covid-19 cases, Johnson said the time had come to “act rapidly”, saying local lockdowns such as in Leicester had worked well.

The decision to not go ahead with the planned next stage of easing lockdown in England appears to also have been made at very short notice, with public health leaders in cities saying they had not been warned in advance.

The prime minister briefed the UK’s devolved governments on Friday morning that he was rowing back on the next phase of the lockdown easing plans, and was planning to make the announcement at noon.

He hosted a phone briefing with all three first ministers at 10am on Friday morning, involving Nicola Sturgeon in Scotland, Mark Drakeford in Wales and Arlene Foster in Belfast, to also brief them on the UK government’s local lockdown decisions in the north of England and Midlands, imposed on Friday night.

Sturgeon was expected to hold an unscheduled media briefing at 2.30pm on Friday to respond to Johnson’s decisions for England. Meanwhile, she issued a statement recommending against any non-essential travel from Scotland to the north-west of England.

Johnson is thought to have been forced to maintain the restrictions because the rate of community infections from Covid-19 has increased in England. This week he had warned fresh measures could be needed to suppress the spread of the virus.

Under updated plans announced by the government in mid-July – when Johnson said he hoped for a “significant return to normality” by Christmas – the series of newly eased rules had been due to come into force on Saturday.

These involved the reopening of leisure businesses such as bowling, skating rinks and casinos, and to potentially allow socially distanced indoor performances, for example at theatres, with pilots of allowing crowds in sports stadiums. Beauty salons would have been allowed to resume “close contact services” such as eyebrow threading or makeup application, while wedding receptions could have involved sit-down meals for up to 30 people.

All these would have been conditional on businesses meeting Covid-19 guidelines.