Sometimes it’s all about the noise. On Wednesday, George Osborne did more to tackle the country’s addiction to sugar than decades of government education campaigns. It was a huge and welcome surprise to campaigners and confounded all of us who believed that the food and drink corporations had got the Conservative party vacuum-packed in a treacle marinade. A punitive tax on soft drinks manufacturers? Osborne Tango’d everyone.

Of course, the noise will do more than the tax. That won’t have much effect on British waistlines or on type 2 diabetes rates for years, if ever. It is a token. But the sound and fury generated by Osborne’s announcement and the coming fight-back from the corporations will. It is the strongest message ever sent by government that excess sugar can be toxic, especially to children and that sugar-pushing corporations are exploiting taxpayers and the NHS. Treating obesity and diabetes costs the NHS £13.8bn a year and, just as for tobacco, the government will tackle the problem by punishing your and the companies’ pockets.

The story of tobacco shows that this is just the first step on a very long road. But the journey is all part of the benefit. Don’t expect this argument to leave TV stations and advertising billboards soon: the tax won’t be introduced until 2018 and every mention of it is another warning to a parent buying a Britvic Drench for a thirsty toddler.

Come 2018, it may be that a good part of the work of reducing sugary drink consumption will be done. Better-off consumers have been moving away from high-sugar fizzy drinks for some time and technology now offers manufacturers more and more by way of no-calorie substitutes for sugar (some of which are, to say the least, unsavoury). As with the deal the government did to get food manufacturers to lower salt content, there may be a chance to get significant change in soft drink formulas just with the threat of the tax stick.

Of course, politicians’ promises are subject to cancellation, especially when they offend core supporters such as food and beverage manufacturers and the retail industry.

In 2011, David Cameron pledged to tackle teenage drinking and the problem of the cheapest booze since the 18th century with a minimum price of alcohol; 40p a unit (a pint of beer has two units), he said, would save 900 lives and prevent 50,000 crimes by the end of the decade. But within a year, sledgehammer lobbying from the drinks industry and the rage of free-market libertarians in the Conservative party forced abandonment of the plan.

Those forces are already at work: Jacob Rees-Mogg MP said on Thursday of the tax proposal “the loser is Conservative liberalism”; his sister Annunziata, a former Tory candidate, is a leader of the new People Against Sugar Tax campaign. That body says it only accepts private donations, but it has “people” on its board associated with consumer rights groups funded by the tobacco industry. It will be interesting to see if Treasury ministers can defend Osborne’s sugar plan against the combined lobbying muscle of the Tory right and business for longer than they did Cameron’s promise on alcohol pricing.

One of the arguments from the alcohol minimum price fight is already being redeployed – that charges such as these unfairly hurt the poor. There’s truth in that. Eight pence on a can of fizz may sound trivial to some. But I live in Leith, one of the poorest parts of the fattest country in Europe: we drink more than two litres each a week and the soft drink containers I see lying around are not all made by Coca-Cola and AG Barr. They are own-brand mega-bottles, which sell for as little as 20p for a litre of high-sugar lemonade or cola, a fifth of what Coke or Irn-Bru cost. So, at a top sugar tax rate of 24p a litre, these drinks will cost Scots more than double.

The sad truth is that the people who are dying earlier because of the diseases that are triggered or exacerbated by sugar are largely the poor. They pay the human cost of cheap sugar and addiction to it.

So while the tax is regressive, it is also self-targeting: that may make it more effective than critics think. It is significant that the greatest success of the soda tax introduced in Mexico, one of the world’s most obese countries, in 2014, has been among the poorest. There sales of taxed soft drinks have dropped 12% across the board, but by up to 17% among poorest groups.

Of course, Mexico isn’t Britain, and the results from France’s soda tax of about one penny a can have been much less impressive. But the UK’s proposed tax level is much higher. Even if the drinks companies swallow the cost rather than pass it on to consumers, there will still be gains. Hundreds of millions will flow (if Osborne keeps his promise) into children’s sports, neatly answering those who still believe, against the evidence, that the best way to address the excess calories modern children eat is through exercise.

It was interesting that, after Tuesday, the soft drinks industry turned its first fire not on the science of sugar and health but on the confectionery and food manufacturers. There was a playground whine: if you’re going to punish us, why not them? The Institute for Fiscal Studies immediately said that children put off by the cost of sugary drinks might spend the money on sweets instead. (There is, unsurprisingly, no research at all that suggests thirsty people choose foods if they can’t have a drink.)

But there is an issue with the huge load of sugar now hidden in processed foods that, unlike sweets and soft drinks, are not even taxed through VAT. Several countries that have looked at wider sugar taxes have rejected them and settled for going for sugary drinks alone, because the administrative burden of policing sugary foods looks costly and complex. It could come, though: Hungary is reporting some success with a wider tax on sugar and fats.

What campaigners and the medical establishment will now press for is “healthy” fruit juices being brought into the Osborne tax scheme. Some have more sugar than Coca-Cola and no more nutritional value; indeed, there’s medical evidence that clear juices without fibre may carry particular risks to the liver. Yet fruit juice is exempt at the moment. It is absurd that drinks such as Robinsons Fruit Shoot – “flavours to help unleash kids’ adventurous side” – can boast of being an item on the five a day of fruit and vegetables. A 200ml glass of My-5 Apple and pear has 18g – four teaspoons – of sugar.

That sort of heartless exploitation of parents and children is what the Osborne tax can go after. Good luck to it.