A PROJECT dubbed the "missing piece in Scotland's rail jigsaw" that aims to improve east-west links looks in serious doubt as the government prepares to announce its priorities in the Strategic Transport Projects Review (STPR).

The Glasgow Crossrail project, priced at up to £187 million, might boast support from enterprise minister Jim Mather, Labour leadership candidates Cathy Jamieson and Iain Gray, and the business community, but it is said to be increasingly seen as unaffordable in the wake of the estimated £3 billion to £4bn cost of a second Forth road bridge.

With the STPR decision rumoured to be expected shortly after the parliamentary recess next month, possibly ahead of the Scottish Transport Conference 2008 on September 16, plans for the priority projects between 2012 and 2022 will also have come under pressure from the economic downturn and the huge surge in commodity prices.

Ministers can expect a bruising row if Crossrail has been dropped, after an earlier study concluded that it would be worth over £1bn to the Scottish economy over 60 years, and passenger use purely at Glasgow High Street, which would become a transport hub, would be three million. It was also seen as vital for improving access to Glasgow and Prestwick airports, particularly in the run-up to the Commonwealth Games in 2014, by when it was due to be finished.

Bill Butler, chair of the Crossrail cross-party group and MSP for Glasgow Anniesland, told the Sunday Herald: "I certainly hope the government isn't minded to ditch Glasgow Crossrail. It would be a completely retrograde and unacceptable step.

"It has cross-party support and would have benefits nationally in terms of the railway infrastructure and the economic development opportunities that would follow from that."

He insisted, however, that he was still "cautiously optimistic" that the government would "exercise common sense" and make the project happen.

A spokesman for the Scottish Chambers of Commerce, which has previously said Crossrail was essential for reducing the economic over-focus on the central belt, said: "Given that we, along with the rest of the nation, are funding £10bn of Crossrail in London, the urgent need to improve public transport provision and increase the capacity of the rail network makes it essential that we should be investing in Glasgow Crossrail."

The project aims to create a direct link between the southwest and northeast of the city for the first time by building a cross-cutting line of 2km of new track that would create new stations at the Gorbals, Glasgow Cross and West Street.

It would also see a further 3.5km of track upgraded along with investment in signalling and electrification of rail services to speed up journey times. As well as improving transport links in the city, it would directly link Ayrshire with the east and north of the country.

A spokesman for the Scottish Council for Development and Industry (SCDI) said it would be "hugely disappointing" if the project was to be rejected. "It's a visionary project linking the north and the south of the city and would have given people from all over Scotland access to Glasgow airport. It would be a real blow to Scotland's global connectivity," he said.

If the project does collapse, it will be seen as a victim of the surge in commodity inflation from the rapid industrialisation of countries like China and India. With the £115m to £187m cost of Crossrail set at 2005 prices, rising costs are now likely to have pushed it much higher. The price of European reinforcing bar steel, for instance, has doubled over the three years to around 770 to 820 (£611 to £650) per tonne.

It would also represent a failure in lobbying by the Labour-dominated SPT, which has been pushing a three-phase version of the project to alleviate cost concerns.

SPT chairman Alistair Watson said: "SPT has been given assurances by transport minister Stewart Stevenson that the Crossrail proposal is being considered as part of the STPR, due to report shortly."

When first minister Alex Salmond gave the Donald Dewar memorial lecture at the Edinburgh International Boook Festival last Tuesday, there was little to indicate which way the government was leaning, with the main emphasis on affordable housing, planning and tourism.

Those who still believe that Crossrail might go ahead might have read a crumb of comfort into a reference to, "channelling record investment into transport infrastructure to improve the connectivity and flexibility of the Scottish economy", but there are numerous other projects that could fall into this category.

A Scottish Government spokesperson said: "The Glasgow cross rail project is being considered as part of the Strategic Transport Projects Review. No decisions have been made on any transport projects currently being considered as part of STPR. Ministers will make an announcement later this year.

"As we have made clear on a number of occasions Transport Scotland is currently reviewing the various funding options and the legislative route for the Forth Replacement Crossing (FRC), and announcements on both these issues will be made later in the year."