Nick Hornby’s novel About a Boy opens with Will Freeman, rich, child-free and aimless, filling out a magazine questionnaire in search of the ‘cool’ profile of its readers. Will is pretty cool. In the past three months, he’s slept with a woman he didn’t know very well (five points). He’s spent more that £300 on a jacket (five points). He’s eaten in a restaurant that serves polenta and shaved Parmesan (five points).

Ten years have passed since the novel was written, a decade in which the price of cool has doubled. An unstructured (‘the loose end of the tailoring spectrum’) wool and cashmere jacket by Paul Smith on www.mrporter.com costs £660. Polenta with shaved Parmesan has been replaced by Rowley Leigh’s Parmesan custard with anchovy ‘soldiers’, followed by venison cooked sous-vide. Cool, like Time, moves on, and what’s in today is out tomorrow.  

But if all ‘cool’ is superficial, there is one measure of coolness that runs deep: behaviour. Even if you went to Rugby and Cam-bridge, were president of the Union and regularly have lunch at The Cinnamon Club, if you behave like an arrogant, self-important idiot, you drop on the cool scale.

Unfortunately, the curious incident of the Chief Whip on a bicycle at night (now known as Gategate) has been played out against the tired old background of class. Although the Rt Hon Andrew Mitchell denies ever using the word ‘pleb’, much has been made of the accusation that the irate cyclist muttered the abbreviation for ‘plebeians’ as a form of insult.

The word derives from the Latin plebs and signifies the non-aristocratic class of shopkeepers and farmers, members of society who could become rich and influential, but never quite patrician. The modern usage has travelled down a predictable fork in the road. In America, it’s a term used for first-year students, mainly at the military academies. In Britain, it is used as a derogatory term for someone lacking in culture or sophistication. In fact, I have never in my English life heard it used.

What is disturbing about Mr Mitchell and Gategate is not the use of a word that is so distinctly uncool, but that he blew his cool so utterly, was crass and obnoxi-ous to people who earn a great deal less than he does, demanding a privilege-the opening of the main gate-that was not in their gift to provide. He used the kind of language that was neither sophisticated nor cultured. And this is the man whose job is to persuade and cajole his colleagues to support the Prime Minister and tow the party line. Lord have mercy upon the Prime Minister.

There was a brief moment when Mr Mitchell could have scored highly on the ‘cool’ register. He could have promptly resigned. Instead of embarrassing a Prime Minister whose record of defending beleagured friends-Andy Coulson-has left him vulnerable, the Chief Whip could have simply said: ‘I blew my cool. I insulted men who were also working late in the night. I demanded special treatment and acted like an ass when it was denied. The Prime Minister deserves better.’ I reckon such a bold and generous move would have got him 10 points.

Meanwhile, seeing as how both Mr Coulson and Mr Mitchell were both strongly recommended to the Prime Minister by George Osborne, I think it might be cool to remove the Chancellor from personnel decisions.

When it comes to distinguishing between plebeians and patrician, between intelligence and stupidity, arrogance and humility, it’s important to steer clear of the mangy foliage and dead limbs of class. Whether the Chief Whip used the P-word or not, this is not an instance of belligerent class warfare, a vaudeville act of privilege, elitism and smugness based on background. It’s a case of manners, plain and simple. As my grandmother, a patrician plebeian, never stopped reminding us, ‘manners are more important than brains’.