British scientists say they have developed a ceiling-mounted Covid "alarm" that can detect anyone infected in as little as 15 minutes.
The sensor, made by Cambridgeshire firm Roboscientific, works by detecting chemicals produced by the skin or present in the breath of those infected with coronavirus.
According to the company:
Early studies by scientists at the London School of Hygiene and Tropical Medicine and Durham University have shown the device has an accuracy of 98-100%, making is as reliable as gold-standard PCR lab-based Covid-19 tests and considerably more so than quick lateral flow tests.
The researchers have stressed their results are at an early stage, with their work published in a paper that is yet to be peer-reviewed.
These "volatile organic compounds" create odour too subtle to be sniffed by the human nose. A study by the Covid alarm's research team showed they could be detected by dogs, but the alarm would be more accurate and more practical.
Milton Keynes-based charity Medical Detection Dogs - which previously trained dogs to sniff out diseases like cancer, malaria and Parkinson's disease - worked with the London School of Hygiene & Tropical Medicine and Durham University to determine if the dogs like Labradors and cocker spaniels can detect coronavirus in humans from odour samples.
Last year the dogs were even trialled at a London train station.
News of the Alarm comes as Boris Johnson is poised to sign off plans to delay the lifting of coronavirus lockdown restrictions in England amid growing concerns about the surge in case of the highly transmissible Delta variant.
Dr Raghib Ali, senior clinical research associate at the University of Cambridge's MRC epidemiology unit, said any increase in Covid patients would have a "significant" impact on hospitals.
"Hospitals are extremely busy at the moment, the emergency departments last month were the busiest they have been for years because of the huge backlog of patients that didn't come in during the previous waves," he told Sky News.
He added: "I expect the prime minister to say that unfortunately a delay is needed to make sure that we don't get to the situation again where the NHS is unable to provide care to all its patients."