SCOTTISH ministers must provide a “cast-iron guarantee” that jobs will be secured at an infrastructure firm where unions have staged a work-in, Labour said yesterday.

As almost 1,000 workers marched on the Scottish Parliament to demand action to save renewables specialist Burntisland Fabrications (BiFab), the opposition party called on SNP ministers to step up.

“It cannot be right that one of Scotland’s biggest sources of renewable jobs is facing administration while renewables are supposed to be a key priority for Scotland’s economy,” Scottish Labour interim leader Jackie Baillie said.

“Workers need a cast-iron guarantee which will allow them to continue to work and prepare for future renewables work. The Scottish government should commit to providing financial support so that the company can remain operational and the jobs are secured and the work remains in Scotland.”

BiFab has given notice that it is going into administration. Scottish Economy Secretary Keith Brown recently told MSPs that a “disputed payment” from a major contractor was the source of the financial problems.

The company’s workforce, at Burntisland and Methil in Fife and Arnish on the Isle of Lewis, numbers around 1,400, with most being contractors.

Since early this week, the workers have carried on labouring on their current orders, with no guarantee that they will be paid.

It is understood that most of the work on the contract in question — with Dutch wind farm contractor SHL — has been completed.

But BiFab has received just 40 per cent of the payment for the project, leaving the firm with a shortfall of tens of millions of pounds.

Yesterday, workers stopped traffic on Edinburgh’s Royal Mile as they marched towards Holyrood, where a rally was held.

Speaking at the gathering, GMB Scotland secretary Gary Smith said: “This work started in Scotland and it’s going to be finished in Scotland.

“Nothing is going out of those yards. There will be no work moved abroad or down south.”

The Scottish government said First Minister Nicola Sturgeon would cut short a trip to a United Nations climate summit to convene talks on the future of the sites.

Unite Scottish chief Pat Rafferty said: “We know, from the last few days, that this is going to be a tough fight.

“But today we say to this parliament before us: the jobs at these yards in Methil, Burntisland and Lewis are our jobs, Scottish jobs, and we will fight tooth and nail to protect them.”