Over 1,000 staff at food manufacturer Heinz's Wigan plant walked out Wednesday night over a sub-inflation pay offer, and sickness and disciplinary procedures.
The wildcat strike brought permanent and casual staff together, as bosses plan to cut temps' pay by 20%.
Wigan Today reported that almost the entire workforce of one of the borough's largest employers downed tools for 24 hours – against union advice – after a show of hands at two mass meetings.
Staff were said to be at boiling point after being offered a below-inflation 3.5% annual wage offer.
They are also angry that the firm is cutting sick pay and tightening disciplinary and absence procedures.
To add fuel to the discontent, details were leaked to their union officials claiming to show that Heinz managers have been granted a £5,000 bonus because the factory generated more than £135m operating profits.
Shop stewards warned day and night shift staff against any protest strike which hasn't been sanctioned by an official ballot, because they would be in breach of contract and the walkout deemed illegal.
But new union Unite's pleas to exhaust the legitimate negotiation procedure, including a legal strike ballot before taking action, was ignored yesterday.
After an hour of debate among hundreds of day staff, they overwhelmingly voted for a 24-hour strike on a show of hands and immediately left the Kitt Green plant in droves.
A Unite steward at Heinz said: "The workforce has said 'enough is enough' and they have gone. The meetings concerned bonuses, manpower, the GI (general increase) itself, calibre of management and ways of work and there was a great deal of dissatisfaction.
"But as a union we have said staff should not be walking out like this because we are still in procedure and should see things through in the proper fashion."
A production worker with 29 years' experience, who asked not to be named, said: "The lads are really mad about the way we are being treated.
"We have gone along with all the company's changes in terms of shift changes and extra productivity which has helped this place, again, make a massive profit – as it has done for every year I have worked here – but this is the way we are treated.
"Hearing that the managers are going to get a £5,000 bonus, when they are saying ours is going to be cut from about £1,000 to nearer £600, is the final straw.
"Then they are suggesting no sick pay or shift premium for the first three days you are off and cutting the temps' pay rate by 20% – which, if they get away with, you can bet they will try on us the following year."