Continuity mistake: While Gordon Tracey searches for the crashed Fireflash wreckage on the seabed, the parting in his hair keeps changing sides from shot to shot.
Continuity mistake: When Scott arrives in Ireland in Thunderbird 1, he starts to land with the landing gear down and you can see wheels on the legs, but when Thunderbird 1 touches down, the wheels have changed to skis.
Continuity mistake: As the second Fireflash crashes, its left wheel housing pod can be seen to be split in two, yet on Fireflash's ascent to the seabed, the pod is intact.
Continuity mistake: Thunderbird 4's laser cutter is of a different scale and at a different angle in relation to the Fireflash engine pylon in close up and long shots.
Continuity mistake: When Scott, Virgil and Gordon are playing snooker at Tracy Island, the balls on the snooker table change position between shots.
Continuity mistake: When Gordon returns to Thunderbird 4 after making contact with the trapped crew, the configuration of the puppet-sized Thunderbird 4 doesn't match the model seen in long-shot.
Continuity mistake: When Gordon is climbing up Fireflash to the cockpit, we see him just about to put the left rubber suckers onto the glass. However, in the close up shot, he is putting it onto the blue metal of the craft.