Some patients are having to wait in ambulances outside hospitals for up to nine hours because of a backlog of coronavirus patients, a health chief has warned.
Tracy Nicholls, chief executive of the College of Paramedics, said paramedics were under "unprecedented pressure" amid a sharp rise in cases over the past few weeks.
In some areas of the country she said ambulance crews had reported having to wait in a queue for nine hours before a patient was admitted to hospital.
She told Sky News' Sophy Ridge on Sunday programme there have also been delays in getting ambulances to people in need, with some waiting "up to 10 hours" in high-pressure areas.
Nicholls said: "We are seeing the ambulance handover delays at a scale we haven't seen before."
Watch: COVID-19 crisis putting 'unprecedented pressure' on ambulance crews
She added: "Our members have reported to us they can wait as little as half an hour. We've had some members wait five, six, seven, eight and even nine hours.
"But I would say the hidden risk - your viewers can see the ambulances at the hospitals - that doesn't take into account the huge number of patients that are waiting for an ambulance that can't get to them."
Hospital admissions because of coronavirus have reached record highs in the last few days as infection rates also soar.
As of 8am on Friday, 29,346 coronavirus patients were being treated at hospitals in England as doctors in many regions warn they are running out of beds.
"We are very used to seeing ambulance services take some strain over the winter months due to the normal pressures we would see any particular year,” Nicholls continued.
"But this year particularly has seen incredible pressure because of the clinical presentation of the patients our members are seeing. They are sicker."
Nicholls said that, while there "does not appear" to be a delay in ambulance response times for category one life-threatening callouts, there is for category three and four calls.
"Category three calls would be things like abdominal pains or falls, and some of those patients in those high-pressure areas have waited up to 10 hours," she said.
It comes as health secretary Matt Hancock said "the pressure on the NHS is very, very bad" as a result of coronavirus.
He told Sky News' Sophy Ridge On Sunday programme: "The single biggest thing that anybody can do is to follow the stay at home guidance."
Things are likely to get worse before they get better for the health service, according to Dr Simon Walsh, deputy chairman of the British Medical Association's consultants committee.
The London-based emergency care doctor said the epidemiology from the previous wave indicates that the situation is likely to worsen over the next two to three weeks.
He told BBC Breakfast on Saturday: "I'm afraid all of us who are working on the front line believe, and this is based on the evidence I'm afraid, that it is going to get worse before it gets better."
Watch: What you can and can't do during England's third national lockdown