Staff of Tube Lines, who maintain and upgrade three lines on London’s busy underground system, are walking out demanding that they become part of Transport for London’s pension scheme.

Tube Lines’ Chief Executive Jon Lamonte said: “Since becoming part of Transport for London all Tube Lines employees have kept their existing terms and conditions of employment."

He added: “Should this industrial action go ahead, we expect it to have no significant effect on Tube services.

"We do not and will not put passenger or staff safety at risk."

RMT general Secretary Bob Crow has spoken of the four-to-one vote in favour of this action, voicing his and the union’s desire to see all those who work under the London Underground umbrella receive the same rights and benefits.

Photo: Getty