The 1911 dated Luger Model 1908 pistol is believed to have been used in the Cambrai attack on 21 November 1917, which saw more than 400 tanks take part and led to a three-mile hole being cut in the German front line.
Wiltshire Police Armourer, Jamie Ross said: "Firearms handed into the police during surrenders are sent for ballistic tests to ensure they haven't been used in crime and are usually then destroyed.
"This live firearm is a part of history and I know that it is a welcome addition to the collection at the Tank Museum.
"Weapons such as these are often forgotten heirlooms which have been taken from past conflicts and passed down over the generations. I am pleased that we have been able to identify this small piece of history and share it with the museum.
"Firearm surrenders play a key role in removing illegally-owned or unwanted weapons from the streets and help ensure that these weapons don't fall into the wrong hands."
The pistol was linked to the Cambrai attack from an inscription in the holster, which reads 'Souvenir of the Big Advance at Cambrai November 1917'.
Museum Curator, David Willey said: "The Battle of Cambrai is a hugely important moment in the history of the Royal Tank Regiment, so to be given this weapon captured during the battle is of real significance to The Tank Museum.
"We are very grateful to the Wiltshire Police for handing it over to us and allowing us to preserve it for the collection."
Anyone with an unwanted or illegally owned firearms are encouraged to contact police on 101 to arrange for surrender.
Published Wednesday 23 October 2019