When he's returning the shotgun, Chris stuffs his pockets with the jewels and drugs of Mrs. Eastby, his pockets bulge to a degree. Moments later, when he enters the study for Chloe's announcement, his pockets are entirely empty.
When Chris and Chloe meet Tom and Nola at the bar, Chloe stands up to greet the other couple, leaving a champagne cocktail on the bar, which disappears in the next shot.
When Tom and Nola play chess, the amount of wine in Nola's glass changes between shots.
When Chris tells his friend about the affair, his right arm is up, then down, then up again between shots.
When Chris finds Nola in the Tate Modern, Nola's left arm repeatedly changes position between shots.
The computer screens on the detective's desk read 'London Police,' which does not exist. It should read Metropolitan Police, City of London Police, or British Transport Police.
In the scene in the Royal Opera House, the performance of La Traviata is, inexplicably, accompanied by piano rather than full orchestra.
An ornate clock face is shown in closeup for several seconds, indicating a crucial time for the main character's murder scheme. The minute and hour hands on the clock are grossly out of sync with each other: the hour hand shows approximately 6:12, while the minute hand shows 44 minutes after the hour.
Nola calls Chris on his mobile when Alec and Eleanor Hewett are visiting. Chris's Motorola phone plays Nokia's default ringtone.
The police would discover Nola's pregnancy obviously. That would make Chris much more suspect, especially after they did DNA checks, which there is no way they would not do.
When Chris steps out of Cartier and returns to his car, he meets a friend who still plays the tennis circuit. As Chris steps around the rear of the car, the boom microphone is visible in the car's side window.
At around 0:35:00 when Chris and Mr. Hewett are in the gun shack at Hedley, Tom walks in late, and Mr. Hewett accidentally calls him Chris.