Other mistake: When Martin Freeman punches in the numbers on the telephone to call Steve Coogan, the numbers he enters are not shown on the telephone's screen.
Other mistake: Sergeant Fisher is never seen wearing any rank insignia. He therefore appears to be an ordinary PC.
Other mistake: When Sgt. Angel meets Joyce Cooper at the hotel, she is making a crossword puzzle. She said "Fascist" and then read the definition, but that word is not 7 across as she says, but 14 down.
Chosen answer: In the pub Danny demonstrates using a ketchup packet to simulate stabbing himself in the eye. Later in the film he returns Nicholas Angel's notebook, hiding a ketchup packet in it. He stabs the pocket with the notebook, causing the ketchup to leak and simulate blood.