NON-ESSENTIAL workers will be stopped from using the London Underground amid warnings that more people will die of coronavirus if tougher measures are not imposed on travel.

British Transport Police said today that the force will be on hand to support rail operators if people who do not need to travel disregard the effective lockdown announced on Monday night.

London Mayor Sadiq Khan had earlier called for a clampdown on all non-essential travel on the Tube after pictures emerged of carriages still packed with commuters.

Mr Khan demanded that employers let staff work from home “unless it’s absolutely necessary” and warned that many commuters are freelancers or on zero-hours contracts.

He has suggested to the government that it provides a “proper package of support” for these workers so that they can stay in isolation at home.

Finn Brennan, district organiser for train drivers’ union Aslef, warned that “people will die” if the government does not shut down building sites and pay for self-employed workers to self-isolate.

Passengers have criticised Transport for London (TfL) for running fewer Tube services, which appears to have caused overcrowding.

Nurse Danielle Tiplady tweeted: “Being on the Tube is making me feel uneasy. It is too busy [and] there is no space for social distancing.”

She urged Mr Johnson and Mr Khan to “go further,” calling on them to “monitor who is getting on the train and allow more services to run.”

Mr Khan has said that more services can’t be run because “growing numbers” of TfL staff are off sick or self-isolating.

Manuel Cortes, general secretary of transport union TSSA, called for police to be deployed at major London stations to ensure that only passengers “providing vital services” are using the Tube.