His credits include Nil by Mouth (1997), The Football Factory (2004), Rise of the Footsoldier (2007), Doghouse (2009), Bonded by Blood (2010), Kill List (2011), Wild Bill (2011), St George's Day and Piggy (both 2012), The Great Train Robbery (2013), Raised by Wolves (2015), The Mummy (2017), King Arthur: Legend of the Sword (2017), Peaky Blinders (2019), Bull (2021), Litvinenko (2022), and Hijack (2023).

[4] In 2004, he appeared as Rod, best friend and sidekick of Tommy, (played by Danny Dyer), in the British hooligan film The Football Factory, which also starred Tamer Hassan, Frank Harper, and Roland Manookian.

[7] His leading role in the 2011 thriller Kill List (2011),[8] attracted positive reviews from critics earning many nominations for the Best Actor, including at the British Independent Film Awards.

[9] In 2011, he also starred in Wild Bill, in a cast which included Charlie Creed-Miles, Will Poulter, Leo Gregory, Liz White, Iwan Rheon, Olivia Williams, Jaime Winstone, Andy Serkis, and Sean Pertwee.

Maskell has previously worked with Davis in Murder in Successville (where he played Frankie Boyle in one episode),[12]The Warm-Up Guy[13] and The Morgana Show.