The characters were sculpted accurately to portray real historical figures and the models of military equipment and weapons were likewise realistic.

Writer-directors Edward and Rory McHenry poured an enormous amount of effort into the animatronic creations and models, known as “supermarionation” that featured accurately rendered period uniforms, architecture and military equipment.[11] Some continuity errors creeped in. During the first battle between the elite Punjabi Guards and the Germans, a Punjabi soldier is seen using a PIAT rocket launcher, but the PIAT was introduced in 1943 while the film is set in 1940. Also, Jackboots on Whitehall features the German airship Hindenburg which was destroyed in 1937. A German tank destroys the Cenotaph to gain access to Downing Street, but the Cenotaph is not located at the junction of Downing Street and Whitehall, it is further down the street. One prominent scene has a crane shot at the village fête, where a direction sign with two arrows is labeled “Upper Trollope” and “Lower Trollope”, apparently as a tribute to Victorian novelist Anthony Trollope. With a focus on the actual period of the Battle of Britain, the following aircraft models were essential to the depiction of the alternative history: Fairey Fulmar MkI, Focke-Wulf Fw 190D, Hawker Hurricane, Junkers Ju 88A, Junkers Ju 87B-2 Stuka, Messerschmitt Bf 109E and Supermarine Spitfire I. In addition, the following models were also featured: Douglas DC-3, Ford 4-AT-A Trimotor, Sopwith F.1 Camel and Zeppelin LZ 129 Hindenburg.