It's a fair cop as Hollywood gives good guys a shot

I've always done the corrupt cop movie thing," says David Ayer. "I feel that take on the police has been beaten to death. I wanted to do something new, and ironically the best way to do that was to have good cops." So, for his new movie, Ayer, screenwriter of Training Day, Dark Blue and S.W.A.T and director of Street Kings and Harsh Times, decided to focus on a pair of good cops, and good friends, Brian Taylor and Mike Zavala, working the beat; Jake Gyllenhaal and Michael Pena star. "In End of Watch, I wanted to show the LAPD as they really are", he says. "When I show it to cops they say, 'Finally. Someone has got it right.'"

Following the savage treatment of Rodney King, police movies such as Internal Affairs and L.A Confidential focused on the battle between good cop and bad cop, and the best way to clean up a city. In contrast, End of Watch is a throwback to the buddy partnership movies of the 1980s. Taylor and Zavala are like Riggs and Murtaugh of Lethal Weapon or Miami Vice's Crockett and Tubbs – edgy cops who flout the boundaries, but when it comes down to the wire have good intentions.

While those 1980s cops clearly inhabited a fantasy world, though, End of Watch wears its authenticity like a badge. Ayer would not consent to have Gyllenhaal in the movie until he was sure that the star would agree to follow officers on the beat for five months before shooting.

On the first day doing a ride-along, the actor witnessed a murder. "We were the second car on the scene to a gang shooting. I was at the forefront of danger and there were moments in the process where I was definitely afraid, but ultimately I had learned tactics and things to use if things were ever to happen," says Gyllenhaal. Three of the officers he met have since become close friends. "When you spend time with police officers from four in the afternoon to four in the morning and see what they have to go through, you see a lot of different things happen", says the actor. "But you soon learn that most of all it's about them doing a service for the public."

It's the human side that End of Watch does so well. These are the most realistically complex cops seen on screen since The Wire. The best scenes are those in which the guys talk about their domestic life, as Taylor ponders whether to marry his girlfriend, played by Anna Kendrick. Not all of the decisions that the partners make come from a good place. Some choices are made to avoid administration or because they are having a bad day at the office, Some officers are better than others. It's true to life.

Ayer warns that audiences shouldn't expect End of Watch to trigger a rash of movies about good cops. "There is so much inherent drama in a corruption story. In Hollywood it is always, 'What are the stakes? Let's raise the stakes!' So it's easy to default to corruption. At the script stage Iwould always get question, 'What is the conflict? What are the stakes?' And I'd say, 'Well, we care about these guys, we love these guys, we believe in them and this relationship and the stakes are how invested we become in them.' But you can't tell anybody that in my business because they are not going to believe that you can pull it off."

Now Ayer can safely say that he has proved the naysayers wrong.

'End of Watch' is released on Friday 23 November