The first draft of the script included a love interest for Nicholas named Victoria. She was cut from subsequent drafts, but a good amount of her dialogue was given to Danny, often without any changes.
The filming of Angel and Skinner's first meeting at the supermarket was filmed over the course of two days. The conversation was filmed entirely from Timothy Dalton's perspective first. The next day, early in the morning, they were to film the conversation with Angel's perspective and close-ups. Dalton, much to the surprise of the crew, showed up early the next morning, and even though he wasn't going to be on camera for that particular portion of the filming, he sat off-camera in Skinner's chair and played the role so that Simon Pegg would be able to have him to work with while filming his part as Angel. Pegg stated it really showed Dalton's professionalism.
Nick Frost only agreed to do the film if he could get to name his character. He was also asked to watch over twenty action films to warm up for the role. He only watched one, Bad Boys II (2003).
When in costume, Nick Frost and Simon Pegg often were assumed to be police officers. Many strangers asked them for directions, and instead of telling the truth they went along with it. They claimed it made them feel powerful.
The judges for the Best Kept Village competition near the end of the film are played by Peter Wild and the mothers of Edgar Wright and Simon Pegg.
Cate Blanchett: Nicholas' ex-girlfriend Jeanine at the crime scene. Blanchett asked to be in the film because of her fondness for Shaun of the Dead (2004).
Steve Coogan: Playing a Metropolitan Police Inspector; appears on-screen to speed the transfer of Nicolas Angel out of London, and reappears near the end with Bill Nighy as Metropolitan Chief Inspector, to plead with Angel to return to London.