Father Brown is a 1974 British detective TV series based on the stories by G.K. Chesterton about Father Brown (Kenneth More), a British Catholic Priest who has outstanding abilities in solving mysteries and crimes.
For the 2013 TV adaptation of G.K. Chesterton stories starring Mark Williams see here.
The following weapons were used in the television series Father Brown:
Webley top-break pocket revolvers are seen in several episodes. As far as it can be said, they all turn out to be Webley "WP" Pocket Hammer, chambered in .320. These revolvers are seen in hands of Professor Gerald Smaill (James Maxwell) in "The Curse of the Golden Cross" (Ep.3), Inspector James Bagshaw (Mark Kingston) in "The Mirror of the Magistrate" (Ep.6), Arnold Aylmer (SPOILER! Highlight to see description)(who turns out to be John Strake (David Buck)) in "The Dagger with Wings" (Ep.7), and John Banks (Anthony Allen) in "The Man with Two Beards" (Ep.10). Strangely, all gunshots of these revolvers sound like pretty quiet clicks.
Webley "WP" Pocket Hammerless (drawing)
One of the elements of the graphic title to the series is a compact top-break hammerless revolver. Same hammerless top-break revolver is a part of the graphic title of "The Three Tools of Death" (Ep.5) where it is seen better. This is a very faithful image of Webley "WP" Pocket Hammerless revolver.
Webley .38 Mk III
A Webley .38 Mk III revolver is a valuable plot item in "The Three Tools of Death" (Ep.5).
Single Action Army
In "The Arrow of Heaven" (Ep.12), Col. Hector "Hickory" Merton (Mike Pratt), a veteran of Indian Wars, carries a holstered revolver that is supposed to be a Single Action Army. Judging by the size of the gun and the holster, this is possibly an "Artillery" model.
Unidentified revolver
A revolver is briefly seen in Philip Aylmer's (Michael Sheard) dead hand in "The Dagger with Wings" (Ep.7). Maybe this is the same Webley "WP" Pocket Hammer that is used in several other episodes but it isn't seen good enough to say for sure.
Giles Carstairs (Christian Rodska) fires a revolver in the climactic scene in "The Head of Caesar" (Ep.11). The scene is set in near darkness, only the muzzle flashes and the most general outlines of the gun are seen.
Pistols
Luger P08
A Luger P08 is the murder weapon in "The Mirror of the Magistrate" (Ep.6). The personality of the murderer who turns out to be (SPOILER! Highlight to see description)Sir Arthur Travers (Philip Stone)) is revealed only in the final scene.
A bright nickel plated M1911A1 pistol is carried by Merton's bodyguard Harris (Antony Scott) in "The Arrow of Heaven" (Ep.12). Merton's security guards carry pistols in typical M1911 holsters.
Flintlock Pistols
Three Flintlock Pistols hand on the wall in Col. James Bohun's manor in "The Hammer of God" (Ep.1). Two flintlock pistols are seen in Aylmers' house in "The Dagger with Wings" (Ep.7). Four flintlock pistols hang on the wall in the village hotel in "The Quick One" (Ep.9).
Submachine Guns
Thompson M1921AC/M1928
Security guards in Brander Merton's house are armed with Thompson M1921A/AC or Thompson M1928 submachine guns in "The Arrow of Heaven" (Ep.12).
Long Guns
Blunderbuss
Arnold Aylmer (SPOILER! Highlight to see description)(who turns out to be John Strake (David Buck)) holds two short Blunderbuss guns (one at a time) in "The Dagger with Wings" (Ep.7). He claims that in fear of black magic that John Strake may use against him, he loads one of the guns with silver.
Flintlock Musket
A Flintlock Musket of unknown model hangs on the wall in Col. Hector Merton's room in "The Arrow of Heaven" (Ep.12). The musket seems to have hunting style short handguard rather than the full length military one.
Unidentified rifles
Several rifles are seen in the guardroom in Brander Merton's house in "The Arrow of Heaven" (Ep.12).
Double Barreled Shotgun
Harry Druce (Richard Heffer) holds a Double Barreled Shotgun with exposed hammers in the final scene in "The Oracle of the Dog" (Ep.2).
Footage
Vickers and Lewis Aircraft Machine Guns
A photo of a WWI era fighter plane Sopwith Camel 2F.1, armed with a Vickers machine gun over engine and a Lewis machine gun in "over-wing" Foster mounting, is seen in "The Arrow of Heaven" (Ep.12). To confirm the presence of a not very well distinguishable Vickers, see here for the same photo in better quality.