This piece of advice comes without charge and can be usefully employed by the full firmament of No 10 press officers, spin doctors, speech writers and advisers. Do I also have the attention of thrusting young Progress readers, all of whom plan on forming their own governments by 2020? Yes? Then I’ll begin.

The first rule of being the prime minister is this: never, under any circumstances, invite comparisons between you and Michael Winner. If you feel that this rule needs explaining, clarifying or reinforcing in any way then abandon a career in elected office immediately. Any populist instinct you once harboured has clearly flown the nest, and your ears have turned to tin. Michael Winner will tell you that he’s enjoyed many bedfellows. Mass appeal wasn’t one of them.

For 40 seconds at PMQs, David Cameron forgot this golden rule. Even as he did so, the sky above Westminster seemed to darken slightly. Time slowed to the speed of Sir George Young’s heartbeat and an icy bead of sweat rolled down Nick Clegg’s furrowed brow. His boss had left the well-beaten track of Commons cliché, and dived headlong into some deeply condescending rhetorical undergrowth. Baying Labour MPs could taste the iron tang of blood as the prime minister floundered, his famed ‘sure’ touch escaping him again.

‘Calm down dear, calm down, calm down…’ he told an irate Angela Eagle, voice initially clear and Winner-esque, but quickly quavering as he tried to reverse from his unfortunate verbal cul-de-sac. Debretts will probably tell you that parroting a car insurance advert during Commons proceedings is not good form. Coming across as patronising? Rude? Sexist? Usually best avoided if you seek to be remembered as a statesman. But impersonating the man who once told reporters that ‘an OBE is what you get if you clean the toilets well at King’s Cross station’? Unforgivable in any polite company and badly off message. Poor Craig Oliver will be tearing his hair out.

By then Ed Balls was bouncing with faux indignation and ill-disguised excitement. Eyes were rolled with enthusiastic melodrama, fingers jabbed accusingly and invective flowed. Some of the frailer ministers on the frontbench shrivelled into the soft leather of their seats, faces white with fear, suits speckled with flecks of the shadow chancellor’s saliva. The Labour party’s most effective attack dog (© all journalists) seems to find himself at the centre of PMQs most weeks, despite being nowhere near the dispatch box.

In the grand scheme of things this unhelpful soundbite won’t matter much on its own, but a pattern is developing at these sessions which the prime minister should arrest. Ed Miliband asks awkward questions, Labour MPs bellow belligerently off-mic, Cameron gets flustered and gives an ill-tempered response. This response is the only parliamentary discourse seen on the on evening news bulletins that night. Labour supporters boo and hiss, Tories cheer their man and those mysterious middle ground voters? Well, who knows – but I bet most of them don’t care much for Michael Winner.