Unknown - Prop Machine Gun

A prop machine gun that has unfortunately alluded us so far in its identification, it's been styled similar to the WW2 German MP40 machine gun.

It's been hand made in metal and painted silver and features wooden grips painted black. It reminds us of a villain henchman gun because of its colour, could it have been made for a spy film or show? We believe it was roughly made in the 70'-80's and wouldn't have been used in a war film due to its inaccuracy to the MP40 and its silver colour, and most probably from a British production. It has a very solid build and nice weight to it, and measures: 720mm x 300mm x 60mm (28.3" x 11.8" x 2.3") and weighs 1.3kg.

Do you know what film or show this prop machine gun was used in? If so we would love to hear from you, anyone correctly identifying this prop will receive a reward.