Nationalise Grangemouth.

The call came thick and fast yesterday after an allegedly smiling chairman Calum Maclean told workers at Scotland's crucial petrochemicals plant yesterday that the firm will axe the site's entire petrochemicals arm in 60 days.

Trade unionists and politicians expressed shock and anger alongside some 800 people facing lay-offs after the company said it "could not see a future for Grangemouth."

Petrochemicals union Unite's general secretary Len McCluskey accused billionaire Ineos owner Jim Ratcliffe of manufacturing the crisis, adding that the affair had "exposed a dreadful frailty at the heart of our energy supply."

He urged Westminster and Holyrood to step in - and nationalise the site if necessary.

The decision throws into doubt the future of the site's crucial oil refinery, which processes most of the petrol that reaches Scotland's forecourts and the Forties pipeline that delivers a third of Britain's oil supplies from the North Sea.

Others said Ineos was holding the country to ransom - and accused the firm of hiding the truth about the "still profitable" plant.

North Ayrshire and Arran Labour MP Katy Clark said: "Ineos have employed dubious accountancy techniques and exploited tax havens to siphon off the profits from this vital resource.

"This suggests that the motives of Ineos are simply to try to attack workers' wages and union representation, and when they realised that local workers would organise a resistance have decided to pull the plug altogether."

She added: "The only long-term solution to this closure is simple - the Grangemouth refinery must be taken into public ownership."

Unite's Scottish secretary Pat Rafferty reported that workers at the plant were devastated.

"We have made further proposals in a last-ditch effort to stave off these catastrophic job losses which we believe are tantamount to economic and industrial vandalism," he said.

"Make no mistake, one man is holding this workforce and this country to ransom and that man is Ineos owner Jim Ratcliffe.

"The ball is now in the court of Jim Ratcliffe and the respective governments in Edinburgh and Westminster and we await their responses."

Ineos Grangemouth Chemicals' complex on the Firth of Forth is the biggest industrial site in Scotland.

Its parent company reported operating profits of £265 million in the last quarter of 2012 alone.

But Ineos management powered down the entire plant and locked out its workforce earlier this week, demanding drastic cuts to pay, pensions and terms of employment.

It has said it will shut completely unless the deal is accepted.

Scottish Trades Union Congress general secretary Grahame Smith said the decision to do so had been taken "on the vindictive whim of an unaccountable billionaire."

The Scottish government has already stated that it is seeking a buyer for Grangemouth. But Labour MSP for Coatbridge and Chryston Elaine Smith said: "It is only by democratic ownership that we can ensure that this vital public resource is run for the benefit of those who work there and for those who rely on its oil throughout the country.

"We also call on the Scottish and British Labour parties to support this demand."