The Top 10: TV series that changed the lead partway through

A collection of popular characters played by different actors

Claire Foy will be officially replaced by Olivia Colman in ‘The Crown’ later this month (Getty)

Thanks to Eliot Kane for suggesting this one.

1. Doctor Who. A BBC educational drama intended to teach history, which became a sci-fi hit with the addition of Daleks, and then a durable cult franchise with the genius idea of “regenerating” the lead when Patrick Troughton replaced William Hartnell in 1966.

2. Dallas. “Miss Ellie was recast after Barbara Bel Geddes left and was replaced by Donna Reed. Didn’t work out and Bel Geddes returned to the role,” says Tom Harris. “Or did I dream it?” asks Angela Timlin.

3. Dynasty. Fallon Carrington Colby was originally played by Pamela Sue Martin before being replaced by Emma Samms, when the character was spun off into its own series, The Colbys. When that was cancelled, Samms returned to Dynasty. Also from Tom Harris.

4. Adam Dalgliesh. Martin Shaw replaced Roy Marsden as Adam Dalgliesh in the TV adaptations of PD James’s detective novels. The best bit is that he also replaced Tim Piggott-Smith in the lead role of The Chief, although he played a new chief constable. Thanks to Star Man and Simon Levack.

5. Alias Smith and Jones. Fifty episodes of the 1970s Western. “My favourite show as a child,” says Jason Lewis. “Pete Duel committed suicide and was replaced by Roger Davis as Hannibal Heyes.”

6. Coronation Street. “Changed several leading characters, most famously young Miss Barlow, who went upstairs and came back down a different person altogether,” says Andrew Clark.

7. Game On. Matthew in the 1990s BBC sitcom changed from Ben Chaplin in the first series to Neil Stuke in the second and third. Nominated by Andy Willetts and Owain Morton. Andrew Ruddle adds that in the second series one of the flatmates asked if the other two wanted to watch Dallas, but the idea was rejected as “we don’t like shows where the main character gets changed without warning”.

8. Blue Peter. The puppy that made its debut at Christmas 1962 died of distemper a few days later and was quietly replaced by a similar-looking dog, named Petra, who appeared on the show for 15 years and was its longest-lasting pet. Nominated by Andrew Graystone.

9. Bewitched. US sitcom about a witch marrying a suburban man that ran from 1964 to 1972, with the male lead, Darrin Stephens, changing in 1969 from Dick York to Dick Sargent, who even looked alike. Thanks to the Colour of Heartache.

10. The Crown. TV series on Netflix about the life of Queen Elizabeth II from 1947 onwards. In the first two series, the Queen was played by Claire Foy, and then, as the monarch became older, by Olivia Colman. Thanks to Robert Boston.

Honourable mention for Steven Fogel, who said that in the Michael Apted series 7 Up, some of the characters seem unrecognisable in the septennial broadcasts since the start of the series in 1964, although they are the same people.

In the “there’s always one” category, Star Man nominated Prime Minister’s Questions.

Next week: Telegrams, such as Lord Charles Beresford declining an invitation from the Prince of Wales: “Can’t possibly stop lie follows by post.”

Coming soon: Politicians’ unlikely relations, such as Johnny Cash, related to Bill Cash, the Conservative MP for Stone.

Your suggestions please, and ideas for future Top 10s, to me on Twitter, or by email to top10@independent.co.uk