Euston Films was the first film subsidiary of a British television company that sought to film entirely on location. To understand how the ‘televisual imagination’ changed and developed in relationship to the parent institution's (Thames Television) economic and strategic needs after the transatlantic success of its predecessor, ABC Television, it is necessary to consider how the use of film in television drama was regarded by those working at Euston Films. The sources of realism and development of generic verisimilitude found in the British adventure series of the early 1970s were not confined to television, and these very diverse sources both outside and inside television are well worth exploring. Thames Television, which was formed in 1968, did not adopt the slickly produced adventure series style of ABC's The Avengers, for example. Instead, Thames emphasised its other ABC inheritance – naturalistic drama in the form of the studio-based Armchair Theatre – and was to give the adventure series a strong London lowlife flavour. Its film subsidiary, Euston Films, would produce ‘gritty’ programmes such as the third and fourth series of Special Branch. Amid the continuities and tensions between ABC and Thames, it is possible to discern how economic and technological changes were used as a cultural discourse of value that marks the production of Special Branch as a key transformative moment in the history of British television.
