OPINION - Keir Starmer crossed a big line when he called Rishi Sunak a liar — he shouldn't have done it

There it was. Not a slip of the tongue, not a mis-speak. A wilful, deliberate statement. And I never thought I’d hear it in a debate between two men at the very apex of public life. It was like a blow, only the man on the receiving end didn’t seem to feel it. Sir Keir Starmer called Rishi Sunak a liar.

First he responded to the PM’s allegations about Labour’s tax plans by saying “that’s a lie”. That’s when I thought to myself that no other leader of a political party in this country would ever have said that, and certainly not without it causing national outrage: front page stuff. And then he said it again, during the PM’s closing statement: “Lies, liar”, he said.

Now, the issue here isn’t the truthfulness or accuracy of Rishi Sunak’s claims about Labour’s tax plans: I quite accept that those claims are, to put it mildly, debatable. Nope. It’s the word, the unmentionable word: liar.

It was the case until about a generation ago that those brought up by a far more scrupulous generation would know that this was a profoundly serious insult. There were a hundred circumlocutions you could use: if Sir Keir had spluttered, “that’s not true!” it would have meant exactly the same thing, but would have been entirely unproblematic. That statement would have referred to what was said, not to the honour of the man saying it.

Once, scrupulous people would use the word “untruth” in denying the veracity of a statement and this too would lack the terrible force of the word “lie”, which implies a deliberate intention to deceive. If you root around the lexicon of unparliamentary language, right at the top of it would be “liar”. It would be the one allegation that you’d be called upon to withdraw, since you were impugning the integrity of the speaker in the most profound way.

It says pretty well everything about the culture right now that the word “liar” has lost its force to the point that it can be bandied around by a would-be prime minister against a serving Prime Minister without outrage. Our sensitivities now are very different from before; far coarser. And it’s especially terrible coming from Sir Keir who is, I would say, a rather decent individual — someone nicely brought up by a churchgoing mother and an upright father. That he said it makes it worse, because it shows it’s normative.

The only way to recover the shock of the word liar is to read the literature of former times, probably more than 50 years ago, which reflects the Protestant ethos which was once standard in British public life. Terence Rattigan’s play, The Winslow Boy, 1946, would require a lengthy preamble to make it accessible to modern audiences because it’s based on concepts that were once absolutely fundamental in society: honour, honesty, truthfulness.

It was based on the real life case of a 14 year-old boy, George Archer-Shee, a cadet at a naval college, who was accused of stealing a five shilling postal order from a fellow cadet in 1908. His brother persuaded his father to fight the allegation against the Admiralty and engaged the services of the most eminent barrister of the day, Sir Edward Carson, who, after interviewing the boy, agreed to take on the case and won.

But the point isn’t just that the boy was accused of theft, itself a mean and shabby offence. It was that his truthfulness was being maligned, and that was something that took away his good name — itself a concept that’s alien to us. And rather than allow his son to be called untruthful, the father ruined himself financially.

Sir Edward was an Ulster Protestant and in his ethos, lies and lying were anathema (which isn’t of course the same as saying that people were always truthful; just that it was deadly to be thought to lie). Indeed it was one of the insults that Protestants levelled at Catholics, that they were equivocal about telling the truth: “Jesuitical” was very much a slur. No schoolboy would call another a liar without expecting to be hit. Another name for the Devil is the Father of Lies.

And the reason why Sir Keir shouldn’t have called the PM a liar is that it impugns his integrity. Saint Thomas Aquinas called a lie “a statement at variance with the mind”, that is to say, your words are at odds with your thinking — that is, your words aren’t signifying reality. Lies are damaging because they undermine the value of language itself.

Obviously, politics is a rough and ready affair, and always has been. But even in days when public discourse was much more pointed and rough than it is now, there were limits, and one of them was that you did not call a man a liar, not even a political opponent. Indeed, especially not a political opponent. Sir Keir should withdraw the word and apologise.

Melanie McDonagh is an Evening Standard columnist