Thames Television, who commissioned this series of the show for ITV, broadcast it in its own region 19 days later on Wednesday 29 January.
Having cornered conman Jimmy Merlin in a suburban office, Steed and Tara prepare to take him in.
When Steed and Merlin awake, they are baffled to find the town completely deserted.
Leaving Tara to sleep it off, Steed - with the reluctant Merlin in tow - discovers a plot to hold the whole country to ransom.
The towns of St. Albans, Watford and Old Hatfield were used as to represent the unnamed town in "The Morning After", the locations in which remain virtually unchanged since filming, with the exception of Old Hatfield's central area.