Sir Anthony Seldon, the historian, told LBC radio: “It's hard to know what would be left of the monarchy. The fact that Jeremy Corbyn is saying that would be seen as an assault on the monarchy. It would be crossing the Rubicon. He would be the first Labour leader who started talking about a reduction in the role of the monarchy. It would be very serious. Presumably he is saying it because he knows it will go down well with his supporters."