गूफ़

After the big pub brawl where everyone gets the crap beat out of them, not one of the major characters has a mark on their faces.

When the police are staking out the postbox, the time on the 'Bulova' clock changes from 11:13 to 12:01 and back to 11:27 later.

An establishing shot of the iconic revolving sign outside New Scotland Yard in Victoria and a zoom to a window several storeys up that building is followed by a view from Commander Swann's office which shows County Hall and the River Thames near Westminster Bridge, as seen from St Thomas's Hospital, about a mile away.

As Brannigan and Thatcher drive up to the post office, they park over the line painted on the street, thus hiding it from view. However, when they leave the post office and enter the car, the car is parked perfectly within the lines on the street.

During the brawl in the pub, a woman wearing a blue skirt and striped top is first seen on the ground floor beside the bar, then on the balcony overlooking the bar, and then finally beside the bar again.

When Lt. Brannigan (John Wayne) arrives in London, Scotland Yard Commander Swann (Richard Attenborough) demands that the American surrender his "Colt Diamondback" revolver. That model was never approved by the CPD as a service weapon.

John Wayne refers to Richard Attenborough's character as being a "lord" whereas his actual title is "sir" which would mean that his is not a lord but a non-hereditary knight of the realm who has been knighted on the recommendation of the current ruling political party (very often for contributing to party funds).

There is no way the head of Scotland Yard would have allowed an American cop to carry a gun about London.

When one of Larkin's henchmen falls from a window, the dummy that takes his place for the impact shot lands head-first and crumples unrealistically.

All the Ford cars used have either SPU or NHK registration numbers. Clearly they've all been registered together and supplied to the film company as a batch from Ford.

While in the yellow Ford Capri, Brannigan chases the assassin who is driving a silver Jaguar. After the silver car jumps the open span of the Tower Bridge, the point of view angle shows the road ahead of him. It reveals a London Bobby in the opposing lane calmly standing in front of the stopped oncoming traffic that he is holding while the scene is shot.

When Brannigan jumps into the drivers seat of the yellow Ford Capri, the car's engine starts without him starting it himself.

Attenborough's character could never have become a policeman in the UK because the actor was well under the height requirement for applicants at the time the film was made.

Brannigan's captain (Ralph Meeker) packs a suitcase for him and gives it to him as he takes him to board a British Airways flight to London. When Brannigan lands in London he is carrying a folded suit carrier bag.

Just after the post van enters the mail depot a line of people pass by one of them is holding an open umbrella as you would if it were raining however it was not, the road was dry as were the cars and no one else had an umbrella.

Late in the film, one of the villains says "your big...fat...rear!" But his lips are clearly saying "arse".

Early in the movie, the informant picks tries to fire an empty Luger. He pulls the trigger twice, and each time there is a loud click. The Luger, as a single-action semi-automatic pistol, would not click when it's empty.

New Scotland Yard does not have a view of the Houses of Parliament or County Hall. The view is actually from the top floor of St Thomas's Hospital beside Westminster Bridge.

Mel Ferrer leaves the Dorchester Hotel to go to Piccadilly Circus but is seen crossing over Westminster Bridge.

Mel Ferrer's character and his henchmen leave the Dorchester Hotel and walk up to Marble Arch then suddenly they're walking up the Mall towards Leicester Square.