THE Government is facing mounting pressure to devolve suburban rail routes into London after new polling revealed most passengers back the proposal.

Transport Secretary Chris Grayling has been accused of putting politics ahead of passengers when a leaked letter showed he opposed devolution to keep the network "out of the clutches" of a Labour mayor.

He later blocked a request by London Mayor Sadiq Khan to hand control of the Southeastern commuter route to City Hall and Transport for London (TfL), saying there was no need for a massive reorganisation.

But just 14% of commuters back his decision to keep the capital's commuter lines in control of train operating companies, according to the YouGov poll, while 58% of passengers said Transport for London (TfL) should have more control over the routes, the survey found.

The findings come after the All Party Parliamentary Group for London - a cross party group of MPs - wrote to the Prime Minister to "register our dismay" at Mr Grayling's decision and call for the TfL's devolution bid to be "urgently re-assessed".

The poll of 1,000 adults, which was commissioned by the Greater London Authority, found that 52% of passengers think Mr Grayling made the wrong decision.

Just 14% think he made the right choice, while 58% think TfL should have more control of commuter rail lines and only 5% think it should have less.

Mr Khan said: "The Government is failing commuters with a terrible service, constant delays and cancellations while fares are increasing every year.

"Commuters deserve to be able to get to work and back on a reliable train service.

"This polling clearly demonstrates that commuters want the Government to give control of commuter rail lines to TfL, so they can get the more frequent, reliable and affordable service that they deserve.

"Conservative MPs and councils are also calling on the Government to review the decision taken by Chris Grayling, the current Transport Secretary, who went back on the previous promise made by his predecessor Patrick McLoughlin.

"It's time for the Transport Secretary to stop burying his head in the sand and listen to what commuters want. This is much more important than party politics - it is about people's jobs, time with their family and quality of life."

A Department for Transport spokesman said: "We are determined to improve journeys for rail passengers across London and the South East.

"The mayor's business plan for the Southeastern train routes provided no extra capacity in peak hours, and there was no funding identified for improvements to infrastructure. These would come at a cost to Londoners or mean re-prioritising other travel schemes in the capital.

"MPs and councillors had raised concerns about the mayor being given control over services for people who could not vote for the mayor. We can deliver services improvements through partnership, without the need for a massive reorganisation."

Mick Cash, general secretary of the Rail, Maritime and Transport union, said: "It is wholly understandable that the overwhelming majority of people want rail services wrestled out of the grubby hands of the private rail companies who have ripped off and wrecked services for over two decades.

"However, just putting the mayor or any other elected politician in charge of these spivs and speculators is not a lasting solution. If we are to end the kind of chaos unleashed by the likes of Govia Thameslink and its Southern operations we need public ownership and public control free from profiteering and exploitation of the travelling public.

"RMT will step up the fight for public ownership of Britain's rail services in 2017."