People in "high-contact" professions, such as taxi drivers, pharmacists and cleaners will be tested for coronavirus even if they don't have symptoms, as part of a pilot in England.
The NHS said employers including Addison Lee and Boots will take part.
Care workers and some NHS staff already have access to "asymptomatic" testing.
As part of the pilot, local authorities in Bradford, Newham, Brent and Oldham, will also offer the tests to those identified as vulnerable to the virus.
The expansion of routine testing is designed to look both at how much demand there is for testing among this group and at how different occupations are being affected by the virus.
People recruited to the pilot through their employer will either be given access to a home test or an appointment at a mobile testing unit via their business.
The councils involved will use the capacity they have at their local testing sites to book specific times for people taking part in the pilot.
A number of NHS leaders have said people working in health and care roles should be tested at least once, if not twice, a week to catch these asymptomatic cases and isolate them, stopping them from unwittingly passing the virus on.
This is now available to care homes, but in the NHS staff without symptoms are only tested if there is spare capacity - not systematically.
This trial will now look at what role asymptomatic testing could play for other occupations who have a lot of contact with the public.
It's not known for sure what proportion of people have the virus without showing symptoms, and exactly what role they play in spreading it to others.
A third of people taking part in the Office for National Statistics' surveillance study tested positive without reporting any symptoms either at the time of the test or immediately before or after.
This is based on a relatively small number of positive tests and does not show how many transmitted the virus onwards - but there is a growing understanding that people can pass on the virus causing Covid-19 without knowing they have it.
The latest test and trace figures for England, for 25 June- 1 July were published on Thursday. They show:
- Of everyone who had their case transferred to the contact-tracing system after testing positive, 3, 366 (77%) were reached and 2,552 provided details for at least one close contact
- From the 77% of positive cases who were reached, 14,892 close contacts were identified, of whom 10,547 (71%) were reached and asked to self-isolate
- Over this period, just over 300,000 new people were tested for Covid-19 under in England, with 1.3% testing positive.
More people were transferred into the contact tracing system than tested positive over this time period because of a time lag in getting results and putting them into the system.
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