The Professionals is a British crime-action television drama series produced by Avengers Mark1 Productions for London Weekend Television (LWT) that aired on the ITV network from 1977 to 1983. In all, 57 episodes were produced, filmed between 1977 and 1981. It starred Martin Shaw, Lewis Collins and Gordon Jackson as agents of the fictional "CI5" (Criminal Intelligence 5, alluding to the real-life MI5).
The Professionals was created by Brian Clemens, who had been one of the driving forces behind The Avengers. The show was originally to have been called The A-Squad. Clemens and Albert Fennell were executive producers, with business partner Laurie Johnson providing the theme music. Sidney Hayers produced the first series in 1977, and Raymond Menmuir the remainder.