The last time Denzel Washington worked with director Antoine Fuqua, playing a corrupt cop in crime thriller Training Day, he won a best actor Oscar. But it’s taken more than a decade for the pair to work together again. Their slick, violent reinvention of 1980s TV spy drama The Equalizer stars Washington as retired intelligence officer Robert McCall, an enigmatic loner with OCD symptoms and latent badass training. Pushed to the brink, he takes on Boston’s Russian mobsters virtually single-handedly, dispatching tattooed thugs with corkscrews, nail guns and other improvised weapons (his day job in a hardware store gives him options here).

Sitting down together in London, Washington and Fuqua talk about the film that brought them back together.

Why did it take so long?

Denzel Washington: Success. We both enjoyed success coming off of Training Day. [To Fuqua] You were stacked up a couple of pictures.

Antoine Fuqua: Yeah. I had Tears of the Sun right after. I didn’t even get to enjoy the Academy awards. I left the next day to start on it. It was crazy. I won’t do that again.

DW: You didn’t get to party?

AF: I didn’t get to do no partying!

DW: Nah, I didn’t party, either. I was in the gym the next morning. That was 2002. I was probably prepping Antwone Fisher. No I’d already shot it, I was going back to editing. Or was it something else? I’m confused.

You nearly did American Gangster together. What happened?

AF: You learn to … navigate. It’s tough. It’s just the business. Some things don’t always add up.

Talking of which, I hear you got paid twice for that movie, Denzel? [A reported $20m (£12m).]

DW: One and a half times. My late agent Ed Limato, God rest his soul, was a master businessman. He said: “You have a contract and it will be honoured.” So it went away for a couple of years, then they called and said Ridley Scott was interested. Then I called you [to Fuqua]. And you were like: “Go do your thing.”

There are some similarities between The Equalizer and Training Day. Corrupt cops, Russian gangsters. Do you think that suggests America’s crime landscape hasn’t really changed?

DW: Who else would you pick? Maybe we should have made it Swedes. Those evil Swedes!

AF: The thing about the Russians is, when we did Training Day, they were really making a lot of noise. They were coming into New York and taking over a lot of the Italian mafia’s turf.

DW: Oh really?

AF: Yeah. Training Day was during the Rampart scandal in LA. On the east coast it was more the Russian mob guys starting to get busted. Ironically, now the Russians are again back in the news in a negative way. I don’t know if it’s coincidence or what.

One of the most abiding images in the movie is the character’s mean stare. There’s a lot of close-ups of your eyes, looking mean.

DW: It’s not even mean. That’s what you took from it. I was thinking about lunch!

AF: I wanted you to see him getting mad. He doesn’t talk much in the movie, so how else do you show that?

Do you use that stare in real life?

DW: I don’t do a stare! I try to work from the inside out, not the outside in.

AF: There’s a “sustained intensity”, I call it, with Denzel, anyway. You can feel it right now, can’t you? He’ll smile and laugh at you, but there’s still an energy. That’s special, man.

DW: My mother used to tell me: “You gotta smile more. Because if you don’t smile, the way you look at people, they’ll think you’re mad at them.”

Do you think people find you intimidating?

DW: Don’t know. Don’t try to be.

AF: I’ve heard people say he’s intimidating. But I know him and he’s one of the nicest people you’ll ever meet and he cares about others. If you come in the room thinking that way, you’ll see what you want to see.

DW: You attract what you fear, right?

There’s a lot of religious symbolism in the movie: Russian icons, tattoos of devils. Should we see your character as some kind of avenging angel?

DW: [to Fuqua]: What’s that tattoo you’ve got?

[Fuqua rolls up his sleeve to show a tattoo of the archangel Michael wielding his sword against the devil.]

DW: An avenging angel.

AF [reading the writing]: Who is like God? None of us. Like Denzel said once, God needs warriors too.

DW: Right. Michael was one of them.

Are you both religious men?

DW: Spiritual.

AF: Sure, spiritual.

Do you go to church?

DW: Yep. I do. Not regularly. I’ll be going Sunday when I’m in New York.

AF: I haven’t been in a while. I went when I was in Pittsburgh seeing my mom. If I’m going to see my mom, I’m going to church!

The Equalizer’s idea of justice is almost literally an eye for an eye, but surely vigilantism isn’t recommended in the real world?

DW: No.

AF: No. But this guy doesn’t go out and hurt people; they come after him. He’s not out just killing people, hunting for the next guy. That’s vigilante. That’s not this guy.

DW: What is the definition of vigilante?

Taking the law into your own hands? He does that, doesn’t he?

AF: Yeah, but let me ask you a question: If you saw a kid being bullied on, and you went over to some kid and said, ‘Stop doing that.’ And they got aggressive, and you had to push one of them against the wall to make him stop, is that vigilante?

I guess that’s being a good citizen.

DW: So he’s just a good citizen.

If I stabbed their eyes out with a corkscrew though …

DW: You say taking the law into your own hands, but the cops in the movie, they take the law into their own hands. What would you be doing with a corkscrew anyway?

Er… maybe I’m a wine waiter. I’m working in a restaurant across the road. Or I’m a journalist and I use my pen? You can have that for the sequel.

DW: We had this ex-navy Seal guy training us. They do use pens and stuff. Eyeglasses is a big one. [Pointing at my glasses] You fold that thing up and jab right in the corner of the eye, that’s a real weapon.

AF: Self preservation. You’re in a room, you gotta go to war, you don’t have a gun. You do what you gotta do.

[Washington takes off his wristwatch – a chunky Audemars Piguet – and bangs it against the table, giving me what could be interpreted as his mean stare.]

Is that a weapon or are you telling me my time’s up?

DW: No, but I mean … a backhand … with this.

Is that why you carry it around?

DW: Free watch. Wife said: “Oh they want you to wear it.”

AF: That’s the first time I’ve seen you wear any jewellery.

DW: I liked it ’cos it had the rubber wristband. Wasn’t too posh. Kind of upscale, but comfortable.

Do you get a lot of free stuff?

DW: [Unconvincingly] No! There’s nothing free in this world.

What about your one-and-a-half-times salary for American Gangster?

DW: Aw! Well, I worked for that!

AF: We prepped that movie. That’s work!

DW: The studio took home something like $200m. I’m not crying for them.

• The Equalizer is released in the UK on 26 September.