RAIL union RMT has condemned an “outrageous decision” to award privateers FirstGroup a lucrative eight-year £3 billion contract to run London Overground.

Transport for London (TfL) announced on Wednesday that First Rail London Limited (FRLL), a subsidiary of FirstGroup, has been awarded the new London Overground operator contract from May next year.

FRLL will take the contract over from Arriva Rail London, promising to deliver more rush hour trains and upgrades to CCTV.

But RMT general secretary Eddie Dempsey criticised London’s Labour mayor Sadiq Khan for failing to bring the service into full public ownership.

TfL still owns most of the Overground rolling stock and sets the routes, timetables and fares.

Mr Dempsey said: “Despite the mayor saying he backs public ownership of rail, the London Overground is being re-privatised on a lucrative eight-year deal that puts profit before passengers.

“It’s beyond belief, especially when a Labour government is bringing the railways back into public hands.

“This is another outrageous decision, landing on the same day we learn that cleaning staff are to be outsourced again despite previous commitments to bring them in-house.

“Transport in London is being turned into a haven for exploitative outsourcing and privatisation and RMT will not accept it.

“We will oppose any attempt by TfL to secure devolved control over publicly owned Great British Railways services while it continues down this path.”

TfL has highlighted that the Overground consistently has some of the highest satisfaction and reliability rates of any rail network in the country.

Welcoming FRLL as TfL’s preferred new partner, London Overground’s head of concession David Thomas said: “London Overground is one of the most popular parts of our transport network and this new concession puts customers at its heart, helping make the service even better.”