Guidance for passengers published by the Government on Tuesday also said that where two metre social distancing may not be possible – such as when boarding or alighting a service – they should turn away from other people.

In addition, transport operators are asked to identify areas where queues may form and look to introduce physical infrastructure, signs and one way systems to ensure safe social distancing.

Operators should also look to move queues to areas with more space to accommodate them, and use social media to alert passengers to stay away from stations until sufficient capacity becomes available.

Commenting on the new guidance, Transport Focus chief executive Anthony Smith said: “Many passengers will welcome the advice to wear a face covering,” adding: “It’s important the transport industry now builds on this guidance so passengers using buses, trains and trams are clear what to expect from their operator as well as what’s expected of them.”

A spokesman for bus user group the Confederation of Passenger Transport said: “When travelling, it is important that people follow instructions on the availability of seats and when buses are full.”

The spokesman added: “Reduced capacity combined with extensive home working will mean greatly reduced fare revenue and sustained investment from Government being required, until passenger numbers return to normal levels.”

In the north east, transport operator Nexus said it is following Government advice closely to provide “a Covid secure environment” on the Tyne and Wear Metro. This includes new signage, floor vinyls and barriers to manage passenger flows and queues, while ensuring social distancing is maintained.

Customer services director Huw Lewis said: “We urge customers to wear face coverings if they need to travel. Metro is an enclosed space and in some areas social distancing may not be possible, which is why face coverings are so important for passengers and staff."

Last week, London’s deputy mayor for transport Heidi Alexander said she didn’t know how fast people are going to return to public transport after the crisis, but commented: “What we do know is public expectations are going to be very different to pre-Covid.”

Addressing a London TravelWatch webinar on how the capital’s transport network may emerge from lockdown, she added: “We are clear we want to avoid a car based recovery to this crisis. If people return to cars in increasing numbers, we do run the risk of replacing one public health crisis with another.”

Heidi also said that widening footways to provide more space for people to move about in a socially distant way provides “a real opportunity to get more people walking and cycling”.

(Photograph: Network Rail)