An indefinite strike launched by workers at a Rolls-Royce factory over the sacking of a union official could spread to the company's plants in the Midlands, it has been claimed.
Amicus said the walk-out by 96 engineers at the Bristol factory will have an immediate impact on work at the site where engines are made for military aircraft.
The union said that Jerry Hicks had been sacked by the company because of his trade union activities.
Mr Hicks was accused of organising unofficial industrial action, which he strenuously denied.
Amicus warned that it could not rule out the possibility that industrial action could spread from the site at Filton which was due to begin at midnight last night.
Doug Collins, the union's deputy general secretary, said: "We believe that Jerry has been attacked because of his work as a union official and we are committed to do everything we can to get him reinstated.
"This is an unnecessary situation, entirely of Rolls-Royce's making and we are calling for them to act now to do the right thing and avert a damaging strike."
Amicus said it was campaigning for the full reinstatement of Mr Hicks.
Rolls-Royce dismissed Mr Hicks about a month ago after accusing him of organising unofficial industrial action and contravening an agreement to implement modern working practices, Derbybased union convenor Steve Wright said.
However, a preliminary hearing of an employment tribunal upheld an appeal by Mr Hicks against the decision and requested his reinstatement, saying he had probably been dismissed on grounds of his trade union activity, Mr Wright said.
The company has refused to reinstate Mr Hicks and has offered him a £50,000 pay-off, which he has refused to accept, Mr Wright added.
He said the strike may spread, with unions now planning to ballot about 1,000 blue collar workers at Bristol about possible industrial action in about three weeks' time.
But Rolls- Royce spokesman warned employees to think carefully before embarking on industrial action.
He said: "This is a local issue, concerning the dismissal of one individual on a charge of gross misconduct.
"Despite his important role as a union official, he organised unlawful industrial action earlier in the summer and attempted to undermine disciplinary procedures agreed between the company and its trade unions. After his dismissal, the union balloted just under 100 employees, out of a total workforce of 3,600 in Bristol, and 55 voted in favour of a strike.
"We have a great business in Bristol and would urge employees considering strike action to think carefully whether supporting the unlawful actions of one individual is in their best interests, or those of our customers."