When Sam leaves hospital you see he was staying in Hyde Ward, room 2612. Hyde is the station that he supposedly transferred from. Hyde 2612 is the number he rings to speak to Frank Morgan.
The surname on the headstones of the graves of Sam's 'parents' is Williams. This was originally to be Sam's surname on the show, but Kudos felt that "Sam Williams" was not striking enough. Co-creator Matthew Graham consulted his daughter and she suggested Tyler after Rose Tyler, from Doctor Who (2005).
In the scene in Morgan's car, he produces a folder titled:
The opening sequence starts with the line: "This is a box, a magical box…" In the original Camberwick Green, the opening poem goes: "This is a box, a musical box
Wound up and ready to play.
But this box can hide a secret inside.
I wonder who's in it today?"
When Sam sits down next to Carol Twilling on the bed, asking "Do things ever get a bit frisky?" the top button of his shirt is undone. The camera cuts away and back, only to find that there are now miraculously two buttons undone, not just one. Sam has not moved in this time.
The third victim's surname is Williams. This was originally to be Sam's surname, but Kudos felt that "Sam Williams" was not striking enough. Co-creator Matthew Graham consulted his daughter and she suggested Tyler after Rose Tyler, from Doctor Who (2005).
The autopsy doctor told Hunt that he had to pry the flower of death from the first victim's severely rigomortised hands, yet he shows the detectives a pristine flower that looks as if it has been freshly picked.
Sam refers to Chunky KitKats. KitKats had been around for years, but the Chunky KitKat would not appear until 1999.
In the scene between Hunt and Tyler which takes place directly after Hunt has been "communicating" his outrage to Dickie by hitting his hand repeatedly with a telephone, Hunt puts his hands in his pockets. However, in the next shot, which is the opposite camera angle, his hands are suddenly back out of his pockets. When the camera angle changes again, they're back in, all with no movement on his part.
DCI Hunt tells Kemble to "Call DI Carling when you're ready to name your source," although at this point Carling was a detective sergeant, not an inspector.
Sam's watch (which we see clearly when he checks it just after the escape attempt) is a quartz movement "analog" with a little window at the bottom where an LCD display shows the date. LCD didn't appear on watches or calculators for another five or six years.
Assuming the action still takes place in the spring of 1973, the football match was played on Saturday 21 April 1973. It ended in a scoreless draw.
The officers watch the 1973 Grand National, won by the legendary Red Rum.
One of the protestors at the textile mill gates that Sam and Annie pass — the sandy-haired man in the brown coat — is John Simms' real-life father.
Goof: The vehicle that Gene Hunt drives is a Ford Cortina Mk3. The registration plate, KJM 212K, shows that it was registered between August 71 and July 72. The vinyl roof and four headlights show that it was one of the top of the range models and the GXL badge which is clearly shown in close-up confirms this. However, the vehicle has some strange anachronistic features. The dashboard is from the 2000E model. Also shown in close-up is a badge comprised of the letter E surrounded by a laurel wreath. This was the badging used on the 2000E model, which replaced the GXL model late in 1973. The car should not be carrying badges for both models, especially as the 2000E model would not be released onto the market until six months after the time that the episode was set.
Anachronism: Dialogue in the episode states that the date was 16 March 1973. However, in the first scene, the song that is played on the soundtrack is "Ballroom Blitz" by The Sweet, which was not released until August 1973.
Goof: Sam conducted the taped interview, stating that it was 'Wednesday 16th March'. In 1973, 16 March was a Friday, not a Wednesday. However, 16 March was a Wednesday in 2005, the year the episode was written.
The shot after Sam runs away from the policeman and sees a billboard that mentions Manchester's "Highway in the Sky", where he was when he was hit by the car, is lifted straight from Back to the Future. In that film, Marty McFly sees a billboard of the Lyons Estate, where he will live in 1985.
In the scene where Sam and Gene realize the room where the victim is kept is soundproof, they take a slow-motion leap onto and over a desk, side-by-side. This is a play on a device frequently used in Starsky and Hutch, the seminal buddy-cop drama of the mid 1970s. Frequently, Starsky and Hutch would be seen leaping over furniture, cars, or any other obstruction in a similar manner to get to the bad guys or the victim.
Cars: In 2005, Sam Tyler drives a Jeep Grand Cherokee. In 1973, the police officer thinks of a jeep as a military vehicle.