More than 800 people are employed at the 200-acre Rolls-Royce site at Ansty, near Coventry.
The factory handles the refit and repair of their aeroplane and marine engines. The company's Trent series of civil aviation engines components are also manufactured on the site.
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A large tent has been put up around the area while investigations continue.
The kind gesture touched the hearts of many who shared and retweeted words of support for the officer on Twitter.
Two workers were forced into a back office as the robbers tried to force their way into a safe, police say.