King of Thieves is the story of the Hatton Garden heist, a real burglary committed by a group of senior citizen criminals over the Easter holiday in 2015. The men – played by Michael Caine, Ray Winstone, Tom Courtenay, and Jim Broadbent – scored an astounding £14 million in jewelry. And they would have gotten away with it completely, had a series of slip-ups not unraveled their operation.

ScreenPicks spoke with writer Joe Penhall about bringing one of the most notorious heists in UK history to the big screen.

ScreenPicks: How did you find your words translated to the screen? Was the film different than you expected or pretty much what you had on the page?

Pennhall: It was a little different. … there were a few things, like … Michael Caine and Ray Winstone, for example, would use quite a lot of Cockney vernacular and criminal vernacular, and a lot of profanity as well, which wasn’t in the script. But you kind of had to let them roll with it, you know? So, some of the language isn’t exactly what I wrote but by and large, it’s pretty much what I had written.

ScreenPicks: Did you have those actors in mind when you wrote the parts?

Penhall: Yeah, for sure. I knew that Michael was interested in doing it and would do it if it was a good script. So, I wrote for him in hopes that he would do it. I knew Ray Winstone … we’re friends and we’ve worked together before, so I really hoped that he would do it. And then I really wanted Jim Broadbent to do it. So, I kind of wrote with them vaguely in mind, and then, when they all agreed to do it, I did rewrites, rehearsed with them very closely, and tailored the script even more closely for them. Which is kind of one of the things I like doing when I write. If you can get great actors who are verbally dexterous and enigmatic, then I really like to rehearse with them and listen to how they talk and their cadence and tone and kind of rebuild the script – tailor-make it for them.

ScreenPicks: Did you mind the improvisation they did with the Cockney vernacular?

Penhall: I didn’t mind with them because they were so good at it. Jim Broadbent is very funny and so are Tom Courtenay and Ray Winstone. Michael Caine can sort of read the telephone book and – they’re all pretty great. With other things I’ve done in the past, I’ve kind of been annoyed by improvising, but with these guys, they’re old pros, so it’s a joy to hear what they come out with.

ScreenPicks: What inspired you to write this story in the first place?

Penhall: I was given a transcript from Scotland Yard of surveillance tapes they had made. They had put the gang under surveillance shortly after the robbery and recorded a lot of the conversations covertly and then transcribed it into a big document about 100 pages long. So, this slab of conversations between these hardened criminals arrived on my desk and it was incredibly intriguing. The way that they spoke, very often in vernacular, sometimes it was impenetrable, it was hard to know what they were talking about. Sometimes it was obvious what they were talking about. They were all liars and exaggerators and confabulators. They were all very self-serving. It was sometimes funny. It was a very strange kind of document. It’s not often that you get transcripts of real criminals talking about their crimes shortly after they’ve committed them. And that’s what lured me in really. It was all this raw material. … I couldn’t resist immersing myself in it and seeing what I could come up with. I wasn’t sure I could come up with anything, but I wanted to try.

ScreenPicks: So all of that in-fighting and backstabbing was present in the transcript? It wasn’t just artistic license?

Penhall: There was a hint of it. If you read the transcripts many times, you started to read between the lines and see that there were rivalries and complaints, and they would kind of bitch about each other and subtly undermine each other. There was a lot of positioning. They all seemed to be quite narcissistic, devious, unreliable and petulant. You had to read between the lines, but it seemed to be there. So, I kind of focused on that and reinforced it and exaggerated it I suppose.

I suppose I had to come up with a theory about what really happened because we all know that they went down to a vault, drilled a giant hole, took some jewelry and they were caught – but that’s really all we know. So, the second half of the film is really my theory that they spent about eight weeks on the loose essentially bickering and betraying each other, wasting time and their opportunity.

ScreenPicks: Despite all their squabbling, the characters are likable – at least at times. Do you attribute that to the writing having comedic elements, the quality acting, or that people just love an underdog story?

Penhall: Well I think for me I just wanted them to be relatable. So there are places where they’re likable and understandable and we can empathize. For example, they’re old, they’re lonely. Brian Reader, the leader of the gang, is bereaved, he misses his wife and really has nothing left to do with this life. That’s very human so we can’t help empathizing. But there are times when they’re deeply unpleasant and self-serving and they turn on each other and they turn on that younger gang member. They’re vicious and they’re cruel. I just felt that it was exciting to create an unvarnished portrait of people who are occasional funny and charismatic and occasionally banal and ugly and no fun at all. That’s kind of how most people are. If you go into a bar on a Friday night, that’s how most people are. They’re neither one thing or the other predominantly. No one is really a hero or a villain, always charismatic or always unbearable.

ScreenPicks: I understand that Jim Broadbent’s real-life counterpart, Terry Perkins, died before principal photography had wrapped. Had you known that would happen – say, you did this project just a year later – would it have changed how you shaped the ending?

Penhall: I think the idea was to not tell their whole life story and not try to tell the story of everything that happened afterward. We tried to confine it to the short period leading up to the robbery and just after, so I think the fact that he died, it wasn’t something I would be compelled to include in the film.

… What I thought was interesting was that he was quite an uptight character. He was also a career criminal who was very self-serving. And my understanding is that in court, the judge, having jailed them, then a year or so later, ordered them to pay back everything they had stolen, or they would be jailed for twice as long. And Terry Perkins found this so shocking and unacceptable that he literally had a massive heart attack and dropped dead the following day. Which I thought was really fascinatingly revealing of his character. … Danny Jones who is played by Ray Winstone, was a lot more philosophical and game and resilient, but Terry Perkins was quite uptight and neurotic. It’s only a small character thing but I think it’s something that Jim knew very well in the film. This was before Terry had died and before we knew what was going to happen, but it was quite interesting that Jim had intuitively channeled this intense, neurotic, uptight character who was probably doomed to die before anybody else.

ScreenPicks: The actors really tapped into the characters then.

Penhall: It was lovely having those actors … they can make anything sound great. Jim’s got a great reputation for comedy, but he can also be incredibly menacing. Michael Caine can be very funny and touching but what I love about him in this film is that he’s pretty nasty. It was wonderful to have that caliber of actor with all that range at my disposal.

Catch King of Thieves in theaters and on VOD and Digital HD Friday, Jan. 25th.