Timeslip was originally recorded on colour videotape, except for episodes 23 & 24, which were recorded in black and white due to the so-called "colour strike" - industrial action by technicians that affected many ITV programmes at this time [REF].
It is believed the original videotapes for the wiped episodes were wiped and re-used by Central in 1982 or 83 after they took over from ATV providing ITV programmes to the Midlands during an archive purge of programmes of their predecessors.