Because Hannay is now being watched – and he does not know who wants to get him – the police for the murder he did not commit, or the people who killed the spy – he has to devise a clever way to get out of his flat. The milkman scene is classic. We see other bait and switch scenes in future spy movies too. Like in James Bond’s The Living Daylights where the enemy spy kills the milkman, then disguises himself as the milkman so he can get into the safe house where a Russian agent is kept who is defecting to the West. Here, Hannay needs the milkman’s uniform as a disguise to try to escape the two guys waiting to kill him.
He tries to tell the milkman the truth – there has been a murder in his apartment, and two mysterious men are waiting to get him next, but the milkman is not buying it. So, Hannay makes up a story that he is having an affair with a woman, and one of the men outside is her husband. Ah, this the milkman understands, and he lets Hannay have his uniform!
This scene demonstrates Hannay is quick on his feet and can think of ways out of jams and pressure situations with relative ease.
It is a great scene, with tension and some comic relief built-in, as the milkman calls to Hannay he forgot the empties!