At least 10 years ago I saw this movie on TV. The action took place in England during Cold War. I vaguely remember that the movie wasn't British, but French (though I can be wrong here). As you can see from the summary below, I remember quite a few things about the movie, but unfortunately not the title. I would really appreciate if someone could tell me the name of this movie. I did try searching for the name myself, but I had no luck finding anything related to the movie.
Note, the summary may contain massive spoilers, but I guess those can hardly be avoided here.
Male lead was a son of some Russian spy and some British actress (apparently both were already dead). The protagonist was comically clumsy and couldn't do anything right. Somewhere at the beginning of the move he lost another job and was planning to drown his sorrow in a cake. In the Cafe, to which he went to eat the cake, he met some dumb blonde girl with whom he instantly fell in love. It's probably worth noticing that during this scene an arrow appeared on the screen leading from protagonists eyes to the chest of the girl (I mean this was a very characteristic scene).
In another scene the protagonist was sharing his troubles with a friend of his late father. I think this man was a Turk. He had his own bar, but it was a guise for his real profession, for he was another soviet spy. So this spy got the male lead involved with stealing some secret document from some government building. I think the document was called Operation Avalanche or something similar and was supposed to contain plans for counter-offensive to potential soviet aggression.
The protagonist attempted to gain access to the government building by pretending to be a door-to-door vacuum cleaner seller (and he was really bad at it). However the documents were a hoax and the British actually wanted the soviets to steal them. So, seeing how the protagonist was incapable of stealing the documents on his own, the people from the building helped him out as much as they could. Even with all this help he barely managed to go out of the building with the documents safely hidden in the vacuum cleaner (or at least that was the initial plan), because he is just that clumsy.
In the meantime, the Turk was visited by two Russian spies who came to collect the documents. Collecting the documents wasn't their only task, they were also tasked with getting rid of everyone who was involved in the action. However the Turk, having been in they spy business for a long time, got wind of this part of the plan and proceeded to kill the Russians. He manages to kill one of them, but the other one got away.
In another scene the Turk along with the protagonist were throwing a rolled carpet into some river. The carpet obviously contained the corpse of the Russian spy, but I'm not sure if the male lead was aware of that.
In don't remember all the details from the rest of the movie, but I remember that the protagonist got the girl (the one I mentioned earlier) involved in the whole mess. I think the girl revealed herself as a member of communist party.
During the climax of the movie, the protagonist was chased through some park by both British agents and the remaining Russian spy. I think that at the start of the scene he was together with the girl, but they got split at some point. Eventually the Russian spy cornered the protagonist, but as he was about to kill him both got surrounded by British forces. While I believe the British agents before were all male, the ones who surround those two are all female and wearing officer uniforms. Among them was the girl. So, after all she wasn't a dumb blonde, but a British officer working undercover. During the last scene of the movie the protagonist gets arrested by the girl and is depressed over it (most likely also by the fact that she deceived him all this time), however the girl wears a meaningful smile on her face (which the protagonist fails to notice) indicating she intends to keep him captive in her arms rather than in some prison. So the girl was much smarter than she let on, while the protagonist was utterly helpless most of the time, but that didn't prevent the girl from falling in love with him (must have been his helplessness).
As for the TV station that I watched it on, I think it was called Europa Europa and was available in Polish. I remember that they broadcasted many really bizarre movies (some of them were R rated, but that didn't prevent the station from showing them in the middle of the day). However the movie in question wasn't R rated nor the most bizarre thing they had.