Blakes 7 Federation Pistol.
The pistol used by the Federation Guards in various episodes, note the rear or the pistol (it also has a slight indent in the end).
This makes is different from Travis's pistol which is seen in Gambit has a domed back and also an extra stripe on the grip fitting.
There is also another version seen in 'Terminal' that Servalan uses which is lacking any red stripes.
The side detailing was originally a razor blade handle, but with these now being very rare and near impossible to get hold of, a model ladder was modified to get it as close as possible to the razor handle.