The lead role of Thermoman was played by Ardal O'Hanlon until 2005, when he was replaced by James Dreyfus for the final series.

Unlike most British sitcoms, creator Paul Mendelson co-wrote the episode scripts together with a large team of writers rather than alone.

The character Arnie Kowalski was initially written as living in the US, but from the third series the writers relocated him to Northolt and developed a relationship for him with Mrs. Raven.

After the second series, writers introduced the idea that George and Janet had married and had children of Ultronian origin who possessed speech, intelligence, and super powers despite their infant age.

In the sixth series, the character loses his old body and takes on a new alias, George Monday, working as a doctor alongside Piers, coinciding with the recasting of the role from Ardal O'Hanlon to James Dreyfus.

Moya Brady's character Avril, George's shop assistant, was written out of the show after just the first series.

Series episode counts varied throughout the run: series one and two had six episodes each, series three through five had ten episodes each, and series six had eight episodes, alongside a Christmas special in 2000 and a Comic Relief short in 2001.

Only three of the six series have ever been released on DVD, with fans petitioning the BBC to release a complete series box set.