Continuity mistake: During the opening sequence, a white car parked outside the prisoner's London flat disappears between shots as he drives up in the yellow Lotus and walks to the front door.
Continuity mistake: While the prisoner is packing for his trip (in the opening title sequence), a beach photo placed in his travel bag rotates itself into a different position between shots.
Continuity mistake: In both the opening and closing sequences, as well as in footage used throughout the series, "Rover" leaves the ocean floor as a transparent sphere, but arrives on the surface colored his usual opaque white.
Continuity mistake: In the opening sequence, prior to the Prisoner being spirited away to the Village, the holiday photo inside his briefcase appears to turn 90 degrees between two quick edits.
Other mistake: In the opening sequence, the zoomed typewriter shows the letter "H" printed as an "X" on the identity card.
Visible crew/equipment: In Number 2's chamber Number 6 refuses his offer and says "You won't hold me" as he turns around and goes to walk out. If you look at the bottom right of the screen you can see the shadow of the boom microphone cast on the floor. (00:15:20)
Revealing mistake: When the helicopter lands in the field with Number 2 and Number 6 inside, if you look as it sets down you can see a different man (an actual pilot) flying and not the dwarf butler. He isn't even wearing the butler's bowler hat. (00:16:57)
Revealing mistake: Obvious stunt double for Number 6 when he jumps out the way of the buggy car on the beach during his escape attempt. (00:31:01)
Revealing mistake: When Rover attacks Number 6 on the beach, in one of the shots of Number 6 falling to the ground, you can see a tether keeping Rover from roving too far. (00:31:47)
Continuity mistake: The Villager Rover attacks changes outfits several times between shots. He's wearing a striped sweater that turns into a pink jacket that turns back into the sweater, etc.
Revealing mistake: Though the Village isn't supposed to have automobiles (only the little "golf cart" transports), there are several parked cars visible in the shot of Rover floating down to attack the fleeing Villager.
Visible crew/equipment: In the foot-chase-on-the-beach scene, there are tracks in the sand from the camera crew's truck. They vanish and then reappear when the camera angle changes.
Revealing mistake: At one point, Rover rolls past the Village retirement home, but the film in this sequence was for some reason shown in reverse. Smoke from the building's fireplace is flowing back into the chimney instead of coming out.
Revealing mistake: When Number 6 first enters the bedroom, the light that hangs from the ceiling is moving as though someone has brushed against it. But there's no one else in the room.
Continuity mistake: The maid comes back to Number 6's house for the feather duster she left behind. While they talk, the duster changes positions on the table all by itself.
Revealing mistake: Number 6 is supposedly flying the helicopter, trying to escape from the Village. There are shadows from the rotor blades crossing his face as he pilots the aircraft. But look closely at the top of the transparent cockpit bubble over his head: you can see the real copter blades - completely stationary and not moving at all.
Continuity mistake: The unfortunate Village resident suffocated by Rover is wearing sunglasses that disappear between shots.
Revealing mistake: No automobiles are permitted in the Village - ever. Yet in aerial shots, a black car is sitting behind Number 2's residence.
Continuity mistake: Watch the stone boat in the background as Number 6 and Number 2 discuss the oldsters having "every comfort." Between shots, the senior citizens vanish from the boat.
Continuity mistake: Rover drags Number 5 back out of the water to the beach and drops him with his feet pointing toward the recovery vehicle. He starts to get up, but when the shot cuts, he's lying flat again and has changed orientation on the sand, his head now pointing toward the vehicle.
Chosen answer: We're led to believe Rover is some kind of robot in the series. According to books on the show, Patrick McGoohan was looking for an unusual guardian for the Village, looked up at the sky, and saw a weather balloon, which was what Rover was.
Captain Defenestrator