Trivial is the default mode of British politics. Whether or not the home secretary did ask civil servants and an aide to help her get out of a group speed-awareness course, and if she did, whether she was right to do so, is not the most urgent issue of the day. Yet, as MPs this week gathered round the Westminster village pump, it pushed immigration, the NHS, Ukraine and the G7 off the agenda. Suella Braverman had few qualifications for high office and even fewer to handle Britain’s vexed immigration challenge. Her workload would indeed be a fit topic of discussion. But she has also, like the archbishop of Canterbury, fallen foul of Britain’s driving speed limits. Offenders are offered a choice between a fine and licence points or a speed awareness course, which they aren’t allowed to attend again in three years. It is alleged that Braverman asked if she might do the awareness course one-on-one instead of in a group. This is apparently a facility offered to some people. Reportedly, Braverman first inquired of a civil servant, who correctly but fastidiously refused it as a private matter. She then asked her political adviser, who inquired and was told she had to do a normal course. For a senior minister guilty of a minor offence this process seems reasonable, albeit with a suspiciously harsh outcome. Braverman took it on the chin, paid the fine and took three points on her licence rather than doing the course. It would take an Alan Ayckbourn to turn this into a full-blown scandalous drama. But for Westminster it has been Only Fools and Horses from start to finish. People in top jobs are surely entitled to have people round them – personal secretaries, drivers, diary-keepers – to ease the borderland between work, family and moments of leisure. There is a borderline between private and public duties that the civil service must respect in the taxpayer’s interest. It will be up to Rishi Sunak and his ethics adviser, Laurie Magnus, to determine if that line was crossed here, and whether the ministerial code has been broken. But in the affair as a whole, Parkinson’s law of triviality has applied: the less the importance, the more the attention. The Braverman affair is like the Chequers chef trying to work out whose lunch should be credited to which departmental budget while the massive defence estimates are being passed on the nod. One upside might be that the home secretary and archbishop of Canterbury form a lobby to induce a less centralist attitude to speed limits. Some make sense, some should be lower and some higher. This should depend on local context, not central guidance. London has been reduced to a heaving morass of roadworks, low traffic neighbourhood diversions and a one-size-fits-all, 20mph speed limit in several boroughs. Opponents of low-traffic neighbourhoods argue that journeys reduced are more than cancelled out by longer distances travelled. London drivers now have eyes only for their speedometers, and it seems few people – not taxis, buses, motorbikes or even police cars – stick to the 20mph limit, a limit now extending across many towns and cities. The result is a vast speed trap available to any local authority eager to boost its income. Braverman’s speeding ticket thus joins Downing Street parties and non-dom spouses in the dressing-up cupboard of British politics. Much such behaviour may be reprehensible, but its evils should be kept in proportion. They are how the system crowds out discussion of things that matter. MPs should go on a seriousness awareness course. Simon Jenkins is a Guardian columnist