To modern ears, it is little more than a flirty, if somewhat baffling, vow of Henry VIII’s love for Anne Boleyn.

But for the Vatican, an oblique reference to “duckys” in one of his letters appears to have proved too much.

The Vatican, it has been claimed, declined to let the BBC film a letter from Henry, in which he details a promise to kiss his lover’s “duckys”, over fears it was not quite suitable.

Other letters are to star in the BBC’s new show Six Wives with Lucy Worsley, the first time the archives have ever been granted permission to film them.

Speaking at the launch of the show, executive producer Emma Hindley disclosed Worsley had not been allowed to film or refer to the letters while in the Vatican archive’s hallowed rooms.