Rory Gallivan suggested a list of “politicians who defected twice”, such as Winston Churchill and Oswald Mosley. I could have compiled two lists: a Top 10 Re-Ratters, of politicians who defected and returned to their original party (Churchill); and a Top 10 Multiple Defectors, who went through several different parties (Mosley). But that would be too specialist, even for me.

1. Alcibiades. Athenian statesman and general. ‏During the Peloponnesian War defected to Sparta (415–412 BC) then Persia (412–411 BC). Then he re-ratted to back to Athens. Dan Kelly and Graham Kirby nominate one of the earliest examples.

2. Charles Williams-Wynn. “Did it three times, which I think is a record,” said Sam Freedman. He was a Whig MP from 1797, became a Tory in the 1810s, a Whig again by 1830, and finally Tory from 1834.

3. Lord Goderich, Prime Minister 1827-28. Started as Tory. With other “Huskissonites” (including Palmerston) he joined Whigs for Lord Grey’s government in 1830. Broke with Whigs over the Irish Church and returned to Tories, serving in Peel’s second government. “I think he’s the only double-switching prime minister besides Churchill,” said John Kenney.

4. Benjamin F Butler. “Nominated Jefferson Davis for president at 1860 Democratic National Convention. Flipped to the Republicans during the Civil War, became Radical Republican leader in the House, but flipped back to Democrats in the 1880s before running as Greenback Party presidential candidate in 1884,” said John Kenney.

5. Emmeline Pankhurst. Started as a Liberal, was an early member of the Independent Labour Party, and was finally a Conservative candidate, although she died before the 1929 election. Nominated by Coastal Retreat.

6. Winston Churchill. Conservative MP 1900-04; Liberal 1904-22, when he lost his seat. Returned as a Constitutionalist, with Conservative support, first in a by-election in 1924 and then in the general election, rejoined the Conservatives when Stanley Baldwin made him Chancellor of the Exchequer in November 1924. He said: “Anyone can rat, but it takes a certain ingenuity to re-rat.”

7. Oswald Mosley. Elected a Conservative MP in 1918, he crossed the floor to sit as an Independent in 1922. Joined Labour in 1924, lost his seat, and was elected in a by-election in 1926. Fell out with Labour and set up the New Party before the 1931 election, but it failed to elect a single MP. Rebranded the party as British Union of Fascists (1932-40), Union Movement (1948-73).

8. Paul Marsden. ‏Elected a Labour MP 1997; joined the Lib Dems 2001; and became the first to recross the floor of the Commons since Churchill, to sit on Labour benches just before the 2005 election campaign. He stood down at that election, but was not actually allowed to rejoin the party. Nominated by Oliver Kamm and Mr Memory.

9. Tasmina Ahmed-Sheikh. Member of both Conservatives and Labour in the 1990s; Tory candidate for the Scottish Parliament in 1999. Defected to Scottish National Party in protest at William Hague’s comments about asylum seekers in 2000, and elected to the Westminster Parliament in 2015. From Alex Massie.

10. Winston McKenzie. Serial parliamentary candidate, who was a member of, although not always a candidate for, Labour (until 2001), Liberal Democrats, Veritas, Conservatives, Unity Party, Ukip and English Democrats (since 2015). Thanks to Will Tucker and Alastair Meeks.

No room, then, for Emma Nicholson. Conservative MP 1987-95, who defected to the Lib Dems until the 1997 election, and was then a Lib Dem peer and a Lib Dem MEP 1999-2009. Last year crossed the floor of the House of Lords to rejoin the Conservatives. (Thanks again to Mr Memory.)

Next week: Best Opening Lyrics (this was how my Top 10s started, on Twitter, so there is a 140-character limit)

Coming soon: Fictional pubs