Trains and stations on London’s biggest commuter rail franchise are being treated with a month-long “coronavirus killer” disinfectant.

Govia Thameslink Railway today announced that it was spraying the “viruscide” at Southern, Thameslink and Great Northern stations and in staff areas.

Its entire fleet of 2,700 carriages, including Gatwick Express trains, are also being treated with the liquid, which sticks to surfaces to prevent the onward transmission of the virus.

Staff equipped with electrostatic wands and backpacks — the same devices used in the Nightingale field hospitals — are using it to decontaminate areas as part of an enhanced cleaning regime.

The firm is running about 2,800 of its normal weekday service of 3,600 trains but social distancing means it has space for only about 10 per cent of normal passenger numbers. The trains are intended only for NHS staff and other essential workers.

All train carriages were already being cleaned every night. The new cleaning product replaces a shorter-lasting disinfectant. It offers similar protection to that being used on Tubes, buses and at Underground stations.

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A new app tells Govia staff when each train carriage was last cleaned with the long-lasting viruscide. A thousand no-touch hand sanitisers are being distributed to stations. Govia staff are taking test swabs of areas treated with the viruscide after a week to ensure it remains effective.

The firm has more than 100 extra cleaners. They are told to focus on passenger and staff “touch points”, such as ticket machines, chip and pin machines, door buttons, tables, grab poles and handles.