The industry agreement which should meet your needs is the one negotiated between The Producers’ Alliance for Cinema and Television (PACT) and The Writers’ Guild of Great Britain (WGGB).

This agreement sets out minimum fee rates for both commissioned scripts and adaptations, and for scripts written to an already-existing format (eg that of an established soap). It specifies the minimum that should be paid for an outline, first and subsequent drafts, and final script, and the stages in the script development and production process at which each proportion of the overall fee should be paid.

It does this for one-off television dramas, for finite television series, for episodes of ongoing television serials (eg soaps), and for cinema films.

It specifies what copyright licences the producer acquires (in addition to the writer’s time in producing the script) for the fees set out, and the further amounts that must be paid in order to option or acquire further rights.

It allows for different levels of fee for new writers and established writers. In practice, though, you will find that you are negotiating with agents for most writers with any sort of television track-record. Agents are familiar with the structure of the PACT-WGGB Agreement,