Local elections are the political equivalent of Year 6 SATs. They don't necessarily determine the final outcome - that is to say, the overall result at a General Election - but they offer a good indication of how things are going and can be extremely helpful in determining what areas require extra attention.
Ruling parties hate them because they inevitably expose areas of failure. In the case of Labour, it's clear someone just hasn't been paying attention in class, and no number of excuses or promises can save Keir Starmer now.
For the Tories, Kemi Badenoch is obviously head girl material, but there's still a lot of hard work to be done. The Greens, meanwhile, have spent too much time behind the bike sheds getting high on their own supply.
As for Reform, well, it's always a bit of a surprise when the supposed class clown turns out to be the clever one, but there can be no denying that Nigel Farage has confounded his critics.
In particular, he has pushed one issue to the fore that no other political party has yet had the guts to truly tackle: immigration. This is going to be the single defining issue of the next election, as these regionals have shown.
The political landscape is now divided into two clear factions on this question. Those on the side of the Greens, who believe in an 'all are welcome' policy, and those who want the numbers to be more tightly controlled and all illegal migration to be halted.
Farage's success demonstrates how much more popular the latter view is among voters outside the usual Left-wing urban bubbles.
Vast numbers of undocumented arrivals, often from countries with cultures very different from ours, are clearly what keeps them awake at night, far more than trans rights or VAT on public schools or Palestine or any other hobby-horse obsession.
In the case of Labour, it's clear someone just hasn't been paying attention in class, and no number of excuses or promises can save Keir Starmer now, writes Sarah Vine
Nigel Farage's Reform UK won more than 1,400 seats at Thursday's council elections
The people of Britain could hardly have sent a clearer message: sort out illegal immigration or face political oblivion.
How many other topics can you think of that have managed to unite so many disparate demographics, from disillusioned ex-Tories to working-class Labour voters to middle-class school-run mums? None, save perhaps the universal adoration of Sir David Attenborough or the late Queen.
Whatever else may divide us - age, wealth, social class, race and even religion - it seems the one thing the Brits are broadly in agreement about is the need to get a handle on illegal immigration.
That is what Nigel Farage has always stood for, and that is what people voted for on Thursday.
No doubt the likes of Polanski and the 'be kind' brigade will sneer and dismiss them all as racist 'little Englanders', but that will only alienate those voters more, especially since the situation is only bound to grow worse.
Last week saw the number of small-boat crossings since 2018 pass the 200,000 mark. The vast majority of these arrivals remain on British soil to this day. According to some calculations, that represents a burden on the British taxpayer of as much as £65 billion over the course of their lifetimes.
But this isn't just about money. The cultural implications of wave after wave of predominately young male migrants coming to our shores are being acutely felt by communities everywhere. There are no official Government figures related to crimes committed by migrants, but barely a week goes by without another horror story making the headlines.
Whatever the statistical reality, the perception is that this group is responsible for far too many crimes, in particular a disproportionately high number of rapes and sexual assaults. And as we all know, perception is nine-tenths of reality when it comes to politics.
Of course, not all asylum seekers or economic migrants are by any means undeserving or exploitative. Far from it. But sadly, over the years a significant number have abused Britain's hospitality, and not only in ways that break the law but also by seeking to impose their culture on ours.
Multiculturalism only works if everyone respects everyone else; otherwise it very quickly turns sour; and that is what has happened in too many parts of Britain.
For years politicians have turned a blind eye to these problems; and now they are paying the price.
Voters are not being unreasonable in voting for Farage; they are simply putting their faith in the only political leader who seems to sympathise or is prepared to listen.
And who can blame them? It is neither reasonable nor fair that people who have no right to be here should drain finite public resources and pose a danger to communities and individuals, especially young girls and women.
It is also perfectly reasonable for people to voice concerns about immigration.
You can't sell people something they don't want to buy. And judging by the election results, voters are no longer buying the Blairite idea of a multicultural Britain open to anyone. If there is one lesson to be learned from Reform's success, it is surely this.
In this respect, both Labour and the Conservatives are at a disadvantage. When in Government, the Tories failed to act, with crossings soaring under their watch.
And while Badenoch has admitted the party made a 'catastrophic error' in failing to tackle the problem, she has yet to be given the opportunity to show that she means business.
Labour is in a similar boat. Having made a song and dance about 'smashing the gangs', Starmer has failed to make any serious inroads, despite throwing even more taxpayer cash at the situation.
For too long, honest, hard-working, law-abiding voters have seen their money frittered away by useless politicians on ungrateful, entitled and often fraudulent grifters who see this country as the world's welfare state. And if voters ever dared complain, they were branded racist. Is it any wonder they've had enough?
Britain should never close its borders to those in genuine peril. But if people continue to feel that they are being taken advantage of, or that their land and their identity are being taken from them, no good will come of it.
So while Labour and the Conservatives strive to distance themselves from their mistakes, Farage presents a 'clean skin', as Dominic Cummings would say. He has always been open about the problem but has never been tested - or tainted - by actual government.
While that may be one of his greatest strengths, it is also his biggest weakness. That, for me, is the ultimate problem with Reform: lack of experience.
The last thing this country needs is another prime minister who doesn't have a clue how to govern. Farage is a brilliant campaigner but he has no experience of high office and seems to shy away from Westminster.
It's almost as though he thinks he's too cool for school. And that, I'm afraid, is never a good sign.