Prime Minister Boris Johnson has so far been relying on the government’s “plan A” measures - such as encouraging take-up of Covid booster and flu jabs - to keep Covid infection rates and death toll numbers down in winter months.
In the past, Mr Johnson has said he would roll out plan B if the measures fail to stop “unsustainable pressure” being put on the NHS.
Plan B includes face masks in certain settings, a return to work from home and potentially vaccine passports.
Matthew Taylor, chief executive of the NHS Confederation which represents the healthcare body, said urgent action was needed to stop the NHS “stumbling into a crisis”.
Taylor told The Guardian: “We are right on the edge – and it is the middle of October. It would require an incredible amount of luck for us not to find ourselves in the midst of a profound crisis over the next three months.
“The government ought to not just announce that we’re moving to plan B, but it should be plan B plus. We should do what’s in plan B in terms of masks…
“Working from home, but also we should try to achieve the kind of national mobilisation that we achieved in the first and second waves, where the public went out of their way to support and help the health service.”
On Tuesday, the UK reported 223 Covid deaths - the highest figure for seven months.
The seven-day average for Covid-19 cases stands at 44,145 a day - one of the highest weekly rates of new reported cases in the world.
Downing Street said it was keeping a “very close eye” on the situation.
Labour leader Sir Keir Starmer urged the government “to be more vocal, to step up and assure the public that they have learned the lessons of last year”.
He said Mr Johnson was showing his “characteristic complacency” in the face of growing warnings from experts.