No evidence of COVID-19 was found in tests on trains used by Britain’s largest rail franchise.
Govia Thameslink Railway (GTR) said checks it commissioned on a random selection of carriages used by its Southern, Thameslink and Great Northern brands all returned negative results.
The tests were carried out up to 23 days after surfaces frequently touched by passengers and staff were treated with an anti-viral disinfectant.
Swabs were taken from areas such as grab rails, tables, toilet handles and door buttons, but no trace of Covid-19 was found.
As well as the long-lasting disinfectant, all 2,700 GTR carriages are sanitised overnight using short-term anti-viral sprays.
An additional 100 cleaners are being deployed.
GTR chief operating officer Steve White said: “We are carrying out a comprehensive testing regime of our trains to ensure that our customers can travel with confidence.
“Passengers can be reassured that the long-lasting viruscide we’re using, more than 100 extra cleaners and hospital-grade cleaning products, are working.
“Please follow the Government advice and wear a face covering.”
GTR also runs Gatwick Express trains, but those services are suspended due to the collapse in demand for flights due to the virus crisis.