For more than a decade Glasgow Chamber of Commerce has been supporting a new rail link to

Glasgow Airport.

We simply wanted our airport connected to the rail system to reduce reliance on an increasingly congested M8.

So we welcomed news early in the new year that the first stage of a Glasgow Metro system had been agreed by Glasgow and Renfrewshire councils to deliver a light rail connection from the airport to rail services at Paisley Gilmour Street Station.

Given we have argued for two previous proposals to provide a direct link to Glasgow Central Station why have we given our support to this new, very different project?

Partly because we believe the project could be the catalyst for something even more ambitious. Councillor Susan Aitken’s Glasgow Connectivity Commission, on which I had the privilege to sit, examined the options for improving the public transport system across the whole city and concluded there were clear gaps, notably in the South Clyde Growth Corridor, where employment centres like the site of the Advanced Manufacturing Innovation District and the emerging life sciences research industry at the Queen Elizabeth University Hospital are as under-served as the airport.

Creating a link from Paisley Gilmour Street Station to the airport and then on through the Growth Corridor to the city centre would have multiple benefits. But that, in turn, would be the first line in a much bigger city-wide Metro system designed to improve links between some of our disadvantaged communities and the city districts where jobs are growing.

On its own, a light rail link between the airport and Gilmour Street Station is not especially convincing, but a line that also connects the airport to the South Clyde Growth Corridor and which possibly sets the standard for a much bigger investment is much more appealing.

Equally we had to acknowledge Transport Scotland’s flat refusal to support the direct link into Central Station. The station, they argue, is at full capacity and needs to expand before any new services can be added. They are adamant that a direct link to the airport would damage existing rail services to communities in Ayrshire and Inverclyde.

Again the Connectivity Commission made recommendations on how expansion could be delivered but any work would likely be a long time in the planning and we need alternatives to the M8 congestion quickly.

Opposition from the Government or from Transport Scotland to an airport rail link hasn’t put us off the case before, but previously there has been no genuine alternative on offer. Now we have Nicola Sturgeon hinting in Parliament that the Glasgow Metro will find favour in the Government’s Strategic Transport Projects Review (STPR) which completes next year. And a commitment to explore the feasibility of a full Metro system is included explicitly in the current Programme for Government.

We are, in backing this first phase, choosing to trust those signals. Ms Aitken has made very clear that she wants to see the full line into the city centre built and the First Minister’s comments suggest we should be optimistic.

We are also trusting that Transport Scotland will put its weight behind the project and, whilst it is frustrating that we may not see explicit backing until STPR is complete, we have not heard such positive mood music in many years.

I can fully understand the sceptics who doubt this new project will make any greater progress than its predecessors. But, for the first time since 2007, it looks as if national government, its transport agency and the local authorities are supporting the same project.

Stuart Patrick is chief executive of Glasgow Chamber of Commerce