Jerry Hicks worked for the Bristol plant for more than 30 years

Jerry Hicks was dismissed over two allegations of misconduct.

Amicus predicted "a difficult battle ahead" and warned action could spread to other sites. The union will ballot members on Wednesday for strike action.

A Rolls-Royce Defence Aerospace spokesman said: "We hope that we can now put this issue behind us."

'Scapegoat'

The union warned that a strike will start on 17 August if the workers backed industrial action.

Ian Waddell, Amicus national officer for the aerospace industry, said: "We greet today's ruling with a real sense of disappointment but not surprise.

"Jerry Hicks has unfortunately been made a scapegoat for what is poor industrial relations at the plant."

Mr Hicks had worked at the Patchway plant for more than 30 years. Up to 400 Rolls-Royce workers walked out following his dismissal.

This issue is not about the trade unions but about the gross misconduct of one individual Rolls-Royce

A four-day disciplinary hearing by Rolls-Royce concluded Mr Hicks was guilty of two counts of gross misconduct.

A Rolls-Royce spokesman said: "This issue is not about the trade unions but about the gross misconduct of one individual.

"This has been a difficult time for all those involved but we hope that we can now put this issue behind us and that all of us at Bristol can work together, using our existing agreements to lay the foundations for a prosperous future for the Patchway site."

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.