- Oleg Penkovsky: Greville, I thought I could make the world a safer place. But I failed. All this, betraying my country, my people, was for nothing.
- Greville Wynne: Alex... of course I forgive you. I have to look after my family too. Easier now there's not going to be a nuclear war. Because Khrushchev withdrew his missiles. Because of you.
- Greville Wynne: [as he is lead away by guards] Because of you. You did it. You did it, Alex. You! You did it. Because of you, Alex! You did it!
- Emily Donovan: We know you're a patriot. We know how hard this must be for you. Colonel, whatever brought you here, it must frighten you more than the danger of you being here.
- Oleg Penkovsky: Khrushchev. Khrushchev frightens me. He is impulsive, chaotic - a man like that should not have nuclear commands.
- Greville Wynne: What if I get caught?
- Oleg Penkovsky: You won't.
- Greville Wynne: You don't know that! They'd execute me, correct?
- Oleg Penkovsky: Not if they found out you are just a courier. That you took packages but didn't know what was in them. They would hold you to trade for one of theirs.
- Greville Wynne: How long?
- Oleg Penkovsky: Just a couple of years.
- Greville Wynne: Oh a couple of years, rotting away in some Russian gulag!
- Oleg Penkovsky: They will not catch us. The KGB will have no idea. Listen, I'm better at this than they are.
- Greville Wynne: Fine. But I'm not.
- Oleg Penkovsky: Look, your work - it is only deception. Controlling your emotion. I watched you do it in Moscow. You did it tonight.
- Greville Wynne: It's really not the same thing.
- Oleg Penkovsky: If we're caught, they will definitely execute me.
- Greville Wynne: Well I'm very sorry but that's your choice.
- Oleg Penkovsky: That's how sure I am that you can do this. I'm betting my life on it.
- Greville Wynne: Oleg - can I call you Oleg?
- Oleg Penkovsky: In English, my name doesn't sound good. Call me Alex.
- Oleg Penkovsky: Now the most important question, if you want to do business in Moscow, I need to know.
- Greville Wynne: Yes?
- Oleg Penkovsky: Can you hold your alcohol?
- Greville Wynne: [leans forward] It's my one true gift.
- [they both laugh and finish their spirits in one gulp]
- Title Card: By 1960, the nuclear arms race had intensified. The United States and Soviet Union now possessed weapons capable of wiping out humanity.
- Title Card: As Khrushchev and his American counterparts traded threats, many feared that the world was on the verge of imminent destruction.