Chris Hopson said the NHS had been expecting a short and “sharper” peak in mid to late January.
But because the infection rate is going down more slowly than in March’s lockdown, due to the increased transmissibility of the new variant now spreading across the country, the NHS is now expecting the peak in early to mid February.
Boris Johnson has said he will review the current lockdown in the week beginning February 15, when he hopes 13.8m of the most vulnerable people will have been vaccinated, which could allow potential easing of some restrictions.
But Hopson said there were “quite worrying trends” that suggested the peak of this wave of Covid in terms of NHS demand would be later than anticipated.
It came as official new figures showed almost half (3,144) of the hospital deaths in England and Wales registered during the last week of 2020 involved coronavirus.
Hopson told the Commons health committee: “It seems now pretty clear the infection rate is not going to go down as it did in the first phase, and it’s going to go down more slowly because of the increased transmissibility of the new strain.
“I think the second thing is infection rates – we’ve talked a lot over the last few days about London and the south-east and the east of England, but what’s very clear is the infection rates are now rising really very rapidly beyond those areas – in the Midlands, the north-west and the south-west.
“That’s a particular worry because trusts in the Midlands and the north have got significant numbers of patients still in hospital from the second surge.
“And in the south-west, because of its smaller bed base, we know it’s less able to absorb pressure than the other regions.
“I think when you take those two things together – we were hoping for a sharper peak that came sooner and shorter, so something, for example, when we saw the peak and started to crest it in mid to late January.
“It now looks like the peak for NHS demand may actually now be in February.
“If that’s right, that basically means there’s a higher level and a more extended period of pressure on the NHS than we were expecting even just a week ago.”
Hopson said England was in a “slight limbo period” where it is unclear if the lockdown restrictions are working or what the impact of the Christmas easing of the rules was.
That question needs to be answered “as soon as we can” to determine whether tighter restrictions are needed, he added.
Meanwhile, the NHS is considering “emergency contingency arrangements” to maximise capacity in areas under greatest pressure.
“This is a really, really, incredibly serious position,” he said.