Tuesday's industrial action by 96 test facility engineers could continue for an indefinite period, the union said.

Jerry Hicks was sacked over misconduct claims, but an employment tribunal provisionally found he had "probably been dismissed on trade union grounds".

Rolls-Royce has urged staff to "think carefully" before going on strike.

A statement from the engineering giant said: "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."

Full hearing

The company said that Mr Hicks had been sacked for organising unlawful industrial action earlier in the summer and attempting to undermine disciplinary procedures - claims he denied.

His case is due to appear before a full hearing within six months.

The union Amicus has called for the full reinstatement of Mr Hicks, who had worked at the plant for 30 years. It also warned it could not rule out the possibility that industrial action could spread.

Around 1,000 workers from the rest of the plant could also be balloted for industrial action.

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