London hospitals risk being overwhelmed "in days" by a "tsunami' of cases, a senior NHS chief has warned.
The chief executive of NHS Providers - which represents hospital and ambulance trusts - said hospitals in the capital are facing an "explosion" in demand at the same time as an unprecedented number of staff are sick or in self-isolation.
Branding it a "wicked combination", Chris Hopson said: "It’s the number of patients that are arriving, the speed with which they’re arriving and how ill they are.
"They talk about wave after wave after wave. The word often used to me is a continuous tsunami."
Mr Hopson's verdict was more bleak than that of other medical experts.
Prof Neil Ferguson of Imperial College London, led modelling warning of 250,000 deaths which prompted the UK's stricter lockdown. He told the BBC surge capacity may not be breached.
Prof Ferguson said: "We think overall, with the capacity which is rapidly being put in place across the country, whilst the health system will be intensely stressed particularly in areas of London, it won't break.
"That we will have enough surge capacity overall of the country to cope with the rapidly growing epidemic we're seeing at the moment."
Mr Hopson told BBC Radio 4's Today programme staff were working on a five- to seven-fold increase in critical care capacity, something never done before.
But he warned extra capacity “is now being used up very very quickly”, saying: "Most of them are hanging on, they’re all hanging on, and we know we’ve got the surge capacity in the Excel centre, but this is filling up very quickly."
A 4,000-bed field hospital called 'Nightingale' is being built in the Excel which is a large exhibition hall in London's Docklands.
Last night Mr Hopson tweeted: "London trust CEOs incredibly proud of how much has been done, how quickly, to clear space/create capacity but they're concerned about how quickly this extra capacity is now filling up.
"Preparation/planning has been incredibly helpful but size of demand surge is off the scale.
"It's evident that a number of hospitals are on a trajectory where their critical care capacity will become full within a few days.
"CEOs report that the NHS London Regional team is working well, and hard, with them to agree the next steps to follow when this happens.
"In the face of this demand hospital, ambulance, mental health and community services have been adapting rapidly to do the very best they can in the circumstances.
"Lots of good innovative solutions to provide best possible care given the enormous challenge being faced."
NHS Providers describes itself as the membership organisation for the NHS hospital, mental health, community and ambulance services that treat patients and service users in the NHS.
Professor Neil Ferguson, of Imperial College London, insisted he believes the health system has the capacity to cope and that the lockdown will lead to a "plateau" of case numbers.
He added: "So we are going to have a very difficult few weeks, particularly in hotspots - London for instance.
"But we think, overall, with the capacity which is rapidly being put in place across the country, that whilst the health system will be intensely stressed, particularly in areas of London, it won't break.
"Perhaps in about three weeks we hope these current measures will start flattening that curve and start bringing numbers down."
