A RAIL link between between Glasgow Airport and the city centre "could be operation by 2025" with funding from the City Deal.

Councillors in Glasgow and Renfrewshire will be asked in to back a business case supporting the construction of either a tram-train line or rapid-transit 'pods' linking the airport and the city, potentially killing off the efforts of campaigners to resurrect a heavy rail option.

The business case has been drawn up by jointly by both councils, and will go before Renfrewshire Council's Leadership Board on December 2 with Glasgow City Council's Executive Body due to give its verdict on December 10.

Leader of Glasgow City Council, Frank McAveety with Amanda McMillan, managing director of Glasgow Airport, and Mark MacMillan, leader of Renfrewshire Council

If approved, the bid for City Deal funding will go forward on December 15 to the Glasgow and Clyde Valley Cabinet, the body responsible for distributing the £1.13 billion cash pot.

A tram-train hybrid was recommended by independent consultants, Aecom, 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. The report was commissioned following the Scottish Government's controversial decision to scrap the Glasgow Airport Rail Link (Garl) in 2009 amid spiralling costs.

Under the proposals, tramcars would run on the heavy rail network between Glasgow Central Station and Paisley Gilmour Street before switching onto a newly-constructed light rail line between Paisley and the airport entrance. It is believed construction could get underway in 2021, with a completion date of 2025.

Frank McAveety, leader of Glasgow City Council and chair of the Glasgow and Clyde Valley Cabinet, said: “We’ve long argued that a new rail link between the airport and the city centre is essential for the thousands of tourists and business travellers who fly into and out of Glasgow every day.

“The airport already supports thousands of jobs but this new rail link, which is the single biggest element of our City Deal, will be the catalyst that takes us to a new level, vastly improving the customer experience and generating even more jobs and inward investment.”

The business case estimates that the scheme will cost £144 million, including construction, rolling stock, inflation, contingency and land purchase - compared to the £92m originally projected in the Aecom study.

The discrepancy is said to be based on the fact that Aecom estimated the cost on 2014 prices, whereas the business case is calculated on what the costs are expected to be by 2025.

It is also understood that the bulk of the land required is already owned by the airport, Renfrewshire council or Network Rail, avoiding the need to buy up parcels of former Garl land which were sold back to their previous owners at a huge loss to the taxpayer.

However, the business case also promises a journey time of 16.5 minutes between the city centre and the airport, shaving several minutes off previous projections.

A Scottish Government feasibility study earlier this year predicted that a tram-train would take around 20.5 minutes, compared 22 minutes by the existing bus service, and warned that it be dogged by timetabling issues and a lack of available space at Glasgow Central.

The second option in the business case is a personal rapid transit system. Under this scheme, with an estimated price tag of £102m, passengers travelling to the airport would disembark at Paisley Gilmour Street and complete their journey to the airport in bubble car-style pods, using bespoke rails completely separate from the heavy rail line. A similar system is used at Heathrow.

However, the move will be a blow to transport campaigners who have been lobbying the airport and politicians to use the City Deal windfall to support their £137m 'NEWGarl' vision.

Amanda McMillan, managing director of Glasgow Airport said: "Improving transport links to Glasgow Airport is a top priority for us, particularly at a time when we are enjoying sustained passenger growth. Over the past 12 months alone we have welcomed an additional one million passengers through our doors, so it is important that improved transport links can be achieved as soon as possible."