A gas engineer was shocked to discover a gun under the floorboards of a home in Addison Road, New Bilton, last Thursday.
The workman called the police as soon as he found the firearm.
Hazel Nicholas, press officer for Warwickshire Police, said the officer involved is keen to reassure people the item posed no danger to the public.
She said: “Police were alerted to the discovery of what is believed to be a deactivated display shotgun under the floorboards. The item is believed to have been lawfully owned by a previous occupant of the property and was taken away for expert examination.”