I have to say I was pleasantly surprised by this gritty thriller from 1973 starring the ever dependable Ian Hendry. He is the Assassin of the film, but he's haunted about his last case which didn't go well. Hendry is excellent as the loner assassin (they usually are) given the case of murdering a Government official who is suspected of passing on national secrets.
The film is set in a grey seventies type Britain, just like Get Carter from 71, and their's a kind of sadness about Hendry's character. You suspect this will not end happily for him.
British viewers will spot a few familiar faces in this enjoyable thriller, from Ray Brooks, Caroline John and Frank Windsor to Celia Imrie (probably most famous for UK comedy Dinnerladies made many years later).