Mr Hicks has vowed to fight on if he is sacked

Jerry Hicks, an Amicus convenor at the Patchway plant, is alleged to have led an illegal dispute and not followed the terms of a working practice agreement.

The hearing was suspended on Tuesday and the union is taking legal advice. Rolls-Royce has not commented.

Mr Hicks said: "If I am sacked then the fight goes on. Mark my words."

He said the allegations were an attack on everyone in the union movement.

Industrial action

The Bristol factory produces and services engines for military aircraft, such as the Eurofighter Typhoon, the Hawk and the Harrier.

The staff who staged the walk-out work at the factory's test facility. A total of 3,500 people work at the Patchway plant.

Ray Bazeley, the site's full-time Amicus official said if Mr Hicks was fired a meeting would be called over a ballot for industrial action.

But he would not comment on the significance of the action on the plant's production.

A Rolls-Royce spokesman refused to comment on the impact of the walk-out or the details of the disciplinary action against Mr Hicks.

"It would be inappropriate to comment on a matter between the company and one of our employees," he said.

"We are following agreed procedures for handling such situations."