Final Battle From Assassination Bureau

The Assassination Bureau is a tongue-in-cheek film made in 1969 based on an unfinished novel, The Assassination Bureau, Ltd by Jack London. It stars Oliver Reed, Diana Rigg, Telly Savalas, and Curt Jürgens.
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Condensed synopsis from Wiki
London, the early 1900s: Aspiring journalist and women’s rights campaigner, Sonia Winter (Rigg) uncovers an organization which specialises in killing for money, the Assassination Bureau Limited. Thinking to bring about its destruction, she commissions the assassination of the bureau’s own chairman Ivan Dragomiloff (Reed).

Far from being outraged or upset, Dragomiloff is amused and intrigued and accepts the commission. The guiding principle of his bureau, founded by his father, has always been that there was a moral reason why their victims should be killed. More recently though, his colleagues have tended to kill more for financial gain than for moral reasons. Dragomiloff, therefore, accepts the commission, intending to purge his board of directors.

With Miss Winter in tow, Dragomiloff sets off on a tour of Edwardian Europe, challenging the members of his board kill him or he will kill them! Little do they realise that this is a plot by Miss Winter’s sponsor, newspaper publisher Lord Bostwick (Savalas), to take over the bureau and plunge Europe into war. Bostwick and the other members of the “Bureau” plan to get rich quick by the “biggest killing” of them all secretly buying stocks in arms factories and then propelling Europe into war by assassinating all the heads of state of Europe at the same time while they attend a secret conference.