The unit of the Inland Revenue which deals with the film industry and the independent sector of the television production industry (LP 10) publishes an annual guide for producers, listing the job functions which it regards as being legitimately engaged on a self-employed basis. However, LP 12, which deals with the broadcasters, does not, and its interpretation of the law is not always the same as that of LP 10. (However, the Revenue has recently been making efforts to ensure that LP10 and LP12 interpret these matters in the same way, and this is reflected in the 2001 edition of the LP10 guidance.)
Before engaging a freelance, you should therefore seek the advice on this important point of the appropriate in-house manager in the ITV company for which you are making your programme.