Audio problem: In the scene near the beginning of the film where Charles and Scarlet are heading to the first wedding, they miss their turn off and so have to reverse on the motorway. You see that Scarlet turns her head around to see out the back of the car and can hear her swearing but her mouth never opens.
Continuity mistake: At the end of the film, after Charles has said "no" to Henrietta in church, Carrie comes to see him. It's pouring rain. He opens the door, being completely dry, decides to go outside to talk to her, and in the next shot about two seconds later, he's absolutely soaking wet.
Continuity mistake: After Simon Callow's funeral, when Hugh Grant and James Fleet are talking by the sea, Hugh is holding up an umbrella. In the shots where the camera is in front of him, the umbrella is resting against the side of his head. However, when the camera changes shot and goes behind him, he is holding the umbrella up nearer the front of his forehead.
Continuity mistake: After Carrie leaves Charles at the cinema he decides to run after her. When he catches up with her they stop on a wide sidewalk, and when he mentions how well he had prepared what he had just said to her, lots of people are walking by when the camera is on Charles, but the street is almost deserted when the camera cuts to Carrie.
Continuity mistake: Half way through Charles and Hen's conversation after Charles comes out of Bernard and Lydia's hotel room a small dark spot appears on the shoulder of Hen's jacket, presumably spit from a previous take of Charles being hugged by her, but before it happens in this take.
Continuity mistake: As Scarlett and Charles are heading to the first wedding, they pass a blue Ford on the motorway, just before they miss the turnoff. They reverse and head off the motorway, as the Ford continues on. When they get to the Church, the same blue Ford is parked on the left as they stop.