Several of the 40 staff at Alan Steel Asset Management in Linlithgow say they have witnessed an elderly man wandering around or heard a male voice when no-one is there, and books have fallen off shelves.

They say such incidents have become more frequent in recent months, which is why Alan Steel, the company chairman, brought in a local historian and a priest, believing an exorcism could be the answer.

The firm is built on the site of a former explosives factory which produced dynamite.

During the First World War there was an explosion at the Nobel factory, and two women workers and the foreman are thought to have been killed. Staff think the poltergeist may be the ghost of the foreman.

Leslie Dick, Mr Steel's personal assistant, said: "I was typing the code into the keypad to open the main office door and heard a man saying, 'Excuse me' - but no-one was there. Another time books had fallen off a shelf and been scattered around the office."

Receptionist Elaine Henderson said: "I can definitely feel a presence when I'm sitting in reception - not a nasty one, but something is there."

Local historian, Bruce Jamieson, and the priest visited the office and spoke to staff yesterday afternoon.

They were unable to confirm if there is a presence but will review the situation in a month before deciding whether or not to refer the mystery to someone who can perform an exorcism.

Mr Steel said: "I think it could be the ghost of the bull market. I haven't checked with the Financial Services Authority to check if my ghost is compliant."

In recent years, Scotland has become a centre for psychologists attempting to explain what causes people to report paranormal experiences.

Last year a team launched a massive experiment to investigate Mary King's Close in Edinburgh, the notorious scene of reported hauntings.