Which item from his most important speech as prime minister did Rishi Sunak decided to leak on Monday? Would it be the NHS crisis, rail strikes, inflation or Ukraine? None of the above: instead it was maths. Why maths? What on earth went through his mind? The cult of maths knows no bounds. It rules global education like no other subject, its status akin to medieval Latin. The reason is that it is so easily measurable. Maths is right or wrong. Its targets are international, its results classifiable, its league tables definitive for any government. Immune to leftwing bias and rightwing ideology, maths can run like a ramrod through every school worldwide, a statistician’s dream. When she was schools minister in 2014, Liz Truss visited Shanghai to look at how the Chinese teach the subject and returned mesmerised. She declared Britain faced “economic decline” if it failed to copy China and didn’t get better at maths. Here, at least, Sunak agrees with her. The prime minister’s hero Margaret Thatcher would have been appalled. She held that what was taught in the classroom was a professional matter and not for politicians. She fought her education minister Kenneth Baker over his national curriculum and resulting testing bureaucracy. She lost. By the time she left office, 90% of the school curriculum was centrally ordained, with hundreds of staff dedicated to testing it. This led to the slow death of extracurricular education – the number of playing fields halved – while parents were ordered “to devote 20 minutes to bedtime stories”. Baker’s school reforms were dubbed by the Modern Law Review, “the high point of elective dictatorship”. Mindlessly competitive school league tables saw schools rewarding – or rather bribing – pupils to score higher grades, in some cases £10 a grade. Centre stage was maths. Maths teachers received bonuses. One head asked for the number-blind son of a friend of mine to be removed as his poor results were “lowering the school’s ranking”. The regime was – and remains – a parody of Dickens’ Hard Times, of children as “little pitchers” to be filled so full of maths. Everyone would agree that children must be taught to handle numbers, and that some professions need special skills, scientific, linguistic and numerical. But that the nation’s economic survival might rest on a universal teenage mastery of complex and abstract concepts soon forgotten is utterly absurd. The world’s most successful economy, the US, was placed 38th at mathematics – with Britain at 17th – in the OECD’s 2018 ranking of student development in its controversial Pisa table. Yet these countries lead the world in scientific research. China has long been Pisa’s golden boy. Yet many wealthy Chinese parents beat on the doors of western schools and colleges, pleading for a liberal education for their children. Like many of my generation, I did basic and advanced maths to age 16. This embraced complex algebra, trigonometry, quadratic equations, differential calculus, the use of logarithms and old-fashioned slide rules. I cannot recall ever using one jot of it, all now forgotten. Nor can anyone I have asked from a reasonably wide circle. It was a waste of time, while I was taught no geography and little history. The maths was and remains extraordinary abstract. My children were not taught how to use a computer or calculator in their work. Such aids were banned from class, a bit like banning compasses from navigation school. Maths sceptics such as John Allen Paulos and Conrad Wolfram have pleaded for arithmetic to concentrate where it is really needed, on the role of statistics, proportion and risk in everyday life. Such concepts are regularly abused in discussion of complex subjects such as Covid-19 or the climate crisis. But they should be taught at primary school, just as reading and spelling are. Paulos’s masterful book from 1988, Innumeracy: Mathematical Illiteracy and its Consequences, can be read in an afternoon. We can be intrigued, even charmed, by numbers. I was fascinated by India’s maths genius Srinivasa Ramanujan, and his relationship with Cambridge colleague GH Hardy. The latter gloried in the beauty of maths and hoped “that my mathematics could never be applied”. Equally I delight in Marcus du Sautoy’s efforts to bring maths to life through broadcasting, for those so inclined. There may indeed be a Hardy or a Turing deep inside anyone, as there may be a concert pianist or an astrophysicist. That is what specialist teachers are for. It does not require compulsory maths to 18. Meanwhile, Sunak ignores the rest of England’s archaic national curriculum. Why not greater emphasis on civics, law and the handling of money? What of physical and mental health, human relations and childcare, or an understanding of group identity and political action? Why ignore basic skills such as speaking, job-seeking and self-presentation? Where are the major government policy announcements on such subjects? These are surely guides down the path through life way ahead of maths. A feature boasted by Sunak’s old school, Winchester, is called “div”. Each day begins with an hour on a subject in the public eye, chosen by a teacher but researched, introduced and conducted by pupils themselves. The objective is “learning to communicate effectively, engaging civilly in discussion and argument”. It lies at the foundation of a liberal education. Div is more core than maths. The national curriculum and its obsession with measurement has degenerated into rote learning and memory. Nearly 40 years old and dating from before the internet, it has become vulnerable to cheating, tutoring and cramming, to serve the purposes not of pupils but solely of a state data bank. It has driven sports, arts and creativity into oblivion and reduced schools to exam factories. If Labour cared, it would not wait for office but appoint a commission of curriculum reform right now. Simon Jenkins is a Guardian columnist