AMBITIONS for a rail link between between Glasgow Airport and the city have been dealt another blow amid claims it has been deliberately left out of plans to enhance Scotland's trains network.

Council leaders in the west of the country have reignited the political row over the long-running plans for the route, claiming Network Rail's decision to omit it from future proposals was "mind-boggling".

The local authority-led body responsible for distributing the £1.13 billion City Deal, announced by the UK and Scottish Governments in 2014 and earmarked to fund the link, has written to the rail infrastructure operator expressing concern over the snub.

It has also challenged Scottish ministers, who are at best lukewarm on the scheme, to come out and support it.

But Network Rail has said the council leaders are misunderstanding the remit of its 'Scotland Route Study', claiming it is not about the creation of new railways but enhancing the current one.

Meanwhile, the SNP Government said that ministers were supportive of the City Deal, but it was up to councils to develop plans on how it should be spent.

Plans for a link from Glasgow Central to the airport originally secured the support of the Scottish Parliament in 2006.

But with spiralling costs, concern about management of the project and its business case and the fears over the impact of the squeeze on public finances, the SNP scrapped the plan in 2009.

It was resurrected as a plan by eight councils in 2014 after the announcement of the City Deal, a cash pot to boost infrastructure over the next 20 years, but is still the subject of some debate as to its merits.

A tram-train hybrid was recommended by consultants in February 2014 as the best way to improve surface access to Scotland's second busiest airport, which can currently only be reached by road.

This would see tramcars run on the heavy rail network between Glasgow and Paisley Gilmour Street, before switching onto a newly-constructed light rail line between Paisley and the airport entrance.

But Network Rail's study into future 'things to do' does not mention the link.

Frank McAveety, chair of the Clyde Valley City Deal Cabinet and leader of Glasgow City Council, said: “The project doesn’t need new lines to be included in this study, it needs enhancements to the existing network, and given that Network Rail has known about it for more than a year, the fact there is no reference to it in the route study is mind boggling.

“We would welcome early talks with Network Rail about how the planned works can be aligned to the City Deal investment in the airport rail link.

“However, this study has been written to meet the aspirations of Scottish Government ministers, who have their hands on the money associated with this plan, and what we crucially need is a demonstration of support from them.”

A Network Rail spokesman said: “The Scotland route study is designed to consider how to best utilise and enhance our existing infrastructure, rather than the creation of new railways. That doesn’t preclude the development of proposals for new lines or stations, however, the route study is primarily about looking at what’s possible within the existing assets.

“Network Rail currently has no plans for a Glasgow Airport rail link, but we are always open to discussing proposals to expand Scotland’s rail network and have been working with the City Deal partners as they develop their business case.”

A Government spokesman said: "We remain fully supportive of the City Deal and our officials continue to engage with the Glasgow and Clyde Valley Partnership to ensure the Deal's success.

"The feasibility study which was presented to the Client Group highlights some challenges to the delivery of any rail link. Glasgow City Council and Renfrewshire Council are now taking this work forward, including discussions with Network Rail.”