“Air pollution is the largest environmental risk to public health.” So says the government’s stark guidance on its own official website. It warns that “between 28,000 and 36,000 deaths every year” are due to “human-made air pollution”, and yes, that’s official. London is one of the cities with the worst air, with its poorest people living in the most air-polluted zones in the country. But now the role played by ultra-low emission zones (Ulez) in the byelection in the west London seat of Uxbridge and South Ruislip risks poisoning green politics. Prime Minister Rishi Sunak has so far gone furthest, putting squalid political posturing as the motorists’ friend before clean air, but there’s no morally acceptable excuse for any party to retreat on this. As a young child who suffered repeated bronchitis attacks, I remember the dramatic effects of the 1956 Clean Air Act, banning domestic burning of coal, which stopped pea-souper smogs so thick that you couldn’t see the bus arriving at the bus stop. After that legislation, there was no smog, and I never had bronchitis again. The greatest advances in health come less from heroic medical breakthroughs than the heroes of public health: when John Snow discovered that contaminated water caused cholera; when Joseph Bazalgette built sewers; the vaccination campaign that followed Edward Jenner pioneering smallpox vaccines. Public health action cut smoking from something that 70% of men did in 1962 to 15% now, and the number of deaths from it is still plummeting. Covid showed how, in an emergency with astounding speed, new vaccines can prevent millions of deaths – a similar state of emergency on bad air, climate and food could do that too. Great homage is paid to this well-known public health history. Prevention is politicians’ magic mantra for an overstretched NHS: it has been said, but not done, for all the years I have covered health issues. If only we could stop people getting sick in the first place … Yet public health suffers when cutting surgical waiting lists is the only measurement that matters. The public health grant has been cut by 26% on a real terms per person basis since 2015-16. I spent a day last week with Ivan Browne, Leicester’s director of public health, to see what these depredations had done to his services. It was an exit interview, and he was free to speak his mind, since he retires next month after a lifetime in the city’s public health sector. Being Leicester born and bred helped him navigate the mega-complexity of dozens of diverse communities dealing with the UK’s longest Covid-19 lockdown. These communities were “not hard to reach”, he says, but “easily ignored”, as his team sought out the genuine gatekeepers to be vaccination “champions” who could influence each group. There were messages tailored to Poles or Somalis, vaccination centres in places people trusted: in a mosque, or on the right side of a street that communities never cross. “We were a pilot [scheme] showing how local contact-tracing works, knocking on doors. But we were the only one, it was never rolled out.” He bangs his head at thinking what that money could do, considering the depletion in trusted school nurses or health visitors. Meg Hillier MP, of the public accounts committee, put it at an “unimaginable” £22bn. “I was hopeful everything we learned would stay, sharing our data and resources across all services. Things [that were] ‘impossible’ happened overnight. But it’s gone, everyone back in their silos, professions back in their boundaries, nothing learned for next time.” He sees little gain from the new integrated care system that is supposed to join up NHS and local council services. Public health remains outside, an add-on, hospitals dominant as ever. “Areas like ours with the most need get less than more affluent places.” We visit his sexual health clinic in a former TK Maxx outlet in the middle of a shopping centre. Brightly coloured, welcoming, discreetly labelled “Haymarket Health”, they dispense free contraceptives and treat infections, with counselling and tracing of STI contacts. Syphilis cases are at their highest level for 75 years in England, with gonorrhoea diagnoses up 50%, the worst since records began in 1918. The reason? Sexual health budgets fell by 17% since 2015. “All my services are pinched,” says Browne. This centre takes 1,000 calls a week, but haven’t the staff to answer more: other callers get a message to call back later. We visit his homeless centre, which has provided free breakfasts for 50 people that morning. In the wet room, where street drinkers are allowed to drink, Lee is knocking back a beer, improved, not cured: he had 29 A&E visits last year but only two since he’s been coming here. But no funds get diverted from hospitals to prevention here. Measles is back, too, due to a steep fall in child vaccinations after a rise in anti-MMR internet scares. The government website warns that current vaccine levels could mean an outbreak of between 40,000 and 160,000 cases in London alone, with vaccination levels well below the 95% needed for herd immunity. Browne says they do what they can to myth-bust and reach the vaccine-hesitant, but that takes resources for local champions. For those who don’t remember, measles is serious and can cause blindness. We know what causes ill health, and we know it’s better and cheaper to prevent than treat. “Habits like smoking, drinking, diet and lack of exercise are believed to account for 40% of all premature deaths,” contributing to a recent fall in life expectancy, says last week’s report from the Social Market Foundation. We need to stop nonsense about the “nanny state”, says this non-leftist thinktank, when higher taxes on cigarettes, alcohol and junk food, with stricter licensing regulations, save lives far more effectively than information campaigns. On obesity, their review found that regulatory interventions saved 1.7 times as many healthy years of life as exhortations: more broadly, 80% of heart attacks in under-75s could be avoided. But still, the government backtracks: the tobacco control plan that promised to deliver a smoke-free England by 2030 is postponed, as are restrictions on junk food advertising and “buy one get one free” deals, while alcohol taxes have fallen in real terms. Environmental pledges have just been judged “unachievable” by Whitehall project assessors. Beyond the reach of public health has been the closure since 2010 of 700 football pitches, 200 school playing fields and 400 swimming pools. Even further beyond the reach of local heroes like Ivan Browne, yet underlying all UK health statistics, is poverty, the Royal Society for Public Health says. That’s what causes a 27-year life-expectancy gap between men and 21 years for women in the least and most deprived areas of the country. But here’s what we don’t know: how to persuade enough voters to care enough about inequality and poverty, the causes of most social blights. To have any chance of fulfilling shadow health secretary Wes Streeting’s promise to shift resources towards prevention, Labour will need to resist the idea that waiting lists are the only gauge of health success. The risk is that Treasury money always flows to what’s easiest to measure. Polly Toynbee is a Guardian columnist