The number of people going to Accident and Emergency departments has fallen by more than half amid concern that those with life-threatening conditions are staying away because of fears over coronavirus.
Official data shows that the number of people attending A&E departments each day has fallen from 25,000 to around 11,000 in just one month.
The number arriving at hospitals seeking urgent cardiac treatment for conditions such as heart attacks has also halved, the figures reveal.
Last month, hospitals were ordered to empty around one third of their beds and discharge all patients who were medically fit in a bid to relieve pressures on the NHS as the coronavirus outbreak took hold.
Those with mild symptoms of the virus have been urged to stay at home, while the majority of people who need appointments with GPs are being offered them via phone or video.
But medics are concerned that many members of the public who are seriously ill and in need of emergency care are staying away for fear of catching coronavirus or putting extra pressure on hospitals.
The statistics, from Public Health England (PHE) show that the number of patients attending A&E has fallen in a host of categories, including cardiac conditions, asthma and gastro-enteritis.
The total number going to A&E has fallen dramatically between 1 March and 29 March, the figures for England show.
Experts said some of this may have been driven by the coronavirus lockdown, with pub closures and restricted travel meaning fewer alcohol-related injuries and car accidents, but doctors have expressed alarm that patients with life-threatening conditions such as heart attacks or stroke are staying away in decisions that could cost them their lives.
Dr Deb Lowe, the national clinical director for stroke, said people were ignoring symptoms and failing to ring 999 because they feared being a burden on the NHS during the Covid-19 pandemic.
She said doctors across the country were seeing “quite striking reductions” in the number of people coming into hospital with symptoms of stroke, adding: “It appears that people aren’t seeking emergency help or going to hospital when they suspect a stroke, possibly due to fear of the virus or not wanting to be a burden on the NHS.”
The Stroke Association said it feared thousands of people could be at risk of severe disability, or even stroke-related death, if they did not act on symptoms.
Sarah Scobie, deputy director of research at thinktank the Nuffield Trust, said it was “a considerable worry that people are keeping away from routine and urgent health services, and also from emergency departments”.
She raised fears that patients who avoided turning to A&E could end up deteriorating rapidly and being taken to hospital by ambulance.
A spokesman for NHS England said: “The NHS is pulling out all the stops to respond to the biggest global health threat in a century, while also ensuring that people can still access the services they need in as safe a way as possible.
“There is capacity across the country to treat all those needing urgent, emergency and other essential care, and we want patients to continue to access services. While patients have rightly responded to the expert advice on staying at home, they should still seek medical help whenever they need it.”