Hundreds of staff at a base for nuclear submarines in Cumbria were evacuated following the report of a suspect device.
BAE Systems, which runs the facility in Barrow-in-Furness, said police carried out an investigation into Wednesday’s incident, but that there was “no perceived threat” to the general public.
The company said a full search of four Astute-class submarines currently being built did not find anything suspicious.
Around 1,700 staff at the site were understood to have been evacuated after police swooped on a part of the Barrow site known as Devonshire Dock.
The company said in a statement: “Working with the emergency services, we are now satisfied there is no immediate safety risk and employees due to come on to site to start any shift after 4pm are being asked to report to site as normal.”
Cumbria Police said earlier that officers were “are on-site at BAE assisting staff”. North West Ambulance Service said it attended as a precaution.
A local newspaper, the Mail, reported an anonymous tip-off had been received about a device onboard a submarine within the dock complex.