Hundreds of workers at Rosyth naval dockyard in Fife yesterday ignored the pleas of union officials and walked out in a row over pension cuts
The Daily Record reported that more than 600 workers - almost all those in the yard at the time-took part in the wildcat strike.
They are furious at changes to their pension scheme.
Babcock International, who run the yard, have told workers they will have to pay more into the scheme but will receive smaller pensions when they retire.
Pension contributions are to go up from 1.5 per cent of workers' pay to six per cent.
Union leaders say the move will slash pensions for a typical long-serving skilled worker from about £21,800 to £18,100.
They have been told the changes are needed to plug a £12million deficit in Babcock's pension fund, which stands at about £465million.
Workers were told of the changes on Monday when negotiations with unions broke down.
Unions held a mass meeting yesterday lunchtime.
In a 621-11 vote, workers rejected the changes and agreed to hold a formal postal ballot on industrial action.
Despite pleas from officials, angry staff also decided to walk out there and then.
A yard insider said: "Everyone feels the proposals to change the pension scheme are very unfair.
"They hit workers on lower wages harder than those on good salaries.
"And there is a lot of anger that the workforce are being told to take most of the pain over the pension fund deficit.
"The company took a pension holiday for six years and a partial holiday for the last three.
"After the vote, the workforce took over the meeting from the unions and decided on the walk-out.
"It sends a message to managers that people are not going to take any more of this."
Unions representing workers at Babcock include Amicus, the GMB, T&G, UCATT and Prospect.
Joint unions convener Raymond Duguid said: "The management at Babcock have got to realise how strongly the workforce feel.
"The trade unions are asking management to come back round the table and find a solution everyone can be comfortable with.
"We are not saying no to any changes at all but we want fairness and equality - and the company should share the pain more."
Labour MSP for Mid-Scotland and Fife, John Park, a former Rosyth dockyard worker, also hit out at the company's bid to impose a new pension deal.
He said: "No one should forget the approach of the trade unions and the workforce following privatisation in 1987 has been central to Rosyth's continued success.
"This would be the first ever imposed change by management on the workforce as a whole and not befitting a major employer in the defence sector.
"I have written to the company today asking them to reconsider their plans."
Babcock declined to comment. Rosyth refits Navy vessels and is expected to play a key role in building two multi-billion pound "supercarriers" which will secure its future. The contract is due to be awarded soon.
The yard employs more than 1100 workers. While 600 walked out, the rest of the staff were on back or night shifts and were not on the site at the time.
The action is only for one day, with staff expected to return to work today.
Engineer Craig Nicol, 44, from Rosyth, said the company had to contribute more to the pension scheme.
He said: "The pension rights on offer to the workforce amount to nothing more than a pay cut by stealth.
"We are all extremely angry about this and are upset that negotiations with senior management have got us nowhere.
"It's sad that it's come to this, but the workers have been through a lot at Rosyth.
"In the last 10 years, the workforce has shrunk from around 7500 to 1200 due to redundancies."
John Pearson, 53, a marine manager from Cupar, said: "Staff are angry at what they see as management intransigence.
"The pension fund is in surplus and the future of Rosyth is secure."