Last week saw the publication of the diaries of Sasha Swire, the wife of an obscure former Conservative MP, Sir Hugo Swire.

Sir Hugo’s obscurity was well merited. He held junior ministerial office but displayed no particular talent. One might have expected that he and his wife would remain in obscurity after he lost his seat at the last election.

But last week Lady Swire published a volume of diaries. The revelations in her account of life as a close friend of David and Samantha Cameron and a fixture in the social set which was in charge of the Conservative Party — and the country — until the Brexit referendum have generated enormous publicity for the book.

Our interest in the book is not, however, in the gossip. It is in the reaction to Lady Swire’s repeated use of the phrase “Jewish lobby”. She writes that the “Jewish lobby” is “infiltrating parliament”.

And she describes how “the Jewish lobby will be throwing the kitchen sink at” Jeremy Corbyn (a man she admires because “he shakes hands with Palestinian freedom fighters”).

Her use of a blatantly antisemitic term is, of course, typical of a certain type of English attitude, for whom Jews will and should always be outsiders — not really us — however much they may be tolerated.

But it is not Lady Swire’s attitude to Jews that is interesting. Rather, it is the reaction of reviewers, reporters and commentators who have devoured the book.

Until this newspaper reported it, there was not a single mention of Lady Swire’s repeated references to “the Jewish lobby” in any published reference to the book. It is as if the idea of a Jewish lobby is so established and obvious that it passes readers by.

And so, dreadful as the book is, it has performed a useful service in reminding us of a battle that must always be fought.