Twelve of the world’s biggest food companies — the people who make the fizzy drinks, the crisps, the chocolate and the burgers — spend somewhere between £500 million and £800 million a year advertising to us in Britain. That is the part you can see: the television ads, the bus-stop adverts and the posts that arrive in your children’s feeds. Add the money that never surfaces in an advertising tracker — the supermarket promotions, the trade deals, the sponsorship of the things we watch and play — and a cautious estimate runs past £2 billion. McDonald’s on its own has topped the food and drink advertising table at more than £85 million in a single year. 

None of this is a surprise. Of course, companies advertise their products. We can argue about whether a burger ad belongs across the road from a primary school, and this year a long-promised set of restrictions finally took some of it off our screens before the watershed. But advertising was never the hard part of this problem, for the simple reason that advertising has to be visible for it to work. We can count it, name the brands behind it, and decide what to do about it. 

But what’s being advertised, and defended, is bound up with the largest preventable burden on the nation’s health — the diet-related illnesses that fill hospital beds and drain the public purse to the tune of £268 billion. Over the past decade a long list of sensible measures has been announced and then delayed, diluted or dropped: limits on multibuy promotions, on advertising, on the sweets stacked by the till. When policy keeps almost happening, and then not happening, it is not unreasonable to ask who is in the room on the days those decisions get made. 

Which brings me to the second kind of spending — the budget line that decides whether any of those rules get made at all. This is the ‘external affairs’ budget that pays for the meetings and the briefings, the ‘clucking good time’ for MPs in a parliamentary event; the well-judged word in the right ear, the carefully drafted response to a consultation. It funds the discrete corporate-affairs firms whose trade is access and persuasion near the top of government. And here is the difference that ought to trouble us: you cannot find out how big it is. 

I went looking. Britain has a statutory register of lobbyists, set up after the last bout of cash-for-access embarrassment, and it sounds like it should answer my questions. It doesn’t. The register lists the names of clients but not a single pound of what they pay. It covers only those who deal directly with a minister or a permanent secretary, which leaves out nearly everyone doing the actual work — the conversations with officials, advisers and backbenchers where policy is really shifted. And the large firms fold their lobbying into a far bigger business of financial PR, crisis work and reputation management, none of it broken down by client, let alone by sector. So the question I want to answer — what share of these firms’ income comes from food and farming — has no answer in the public record. Not because nobody has tried counting. Because the system is built so the sum cannot be found. 

Set those two budgets side by side and the industry line – “but we just want to help” – gets harder to defend. A British citizen can discover, more or less to the pound, what the food industry spends to persuade her to buy a product. She can discover almost nothing about what it spends to persuade her government to leave that product alone. We’ve focussed on the cheaper, more visible half of the influence economy, and left the more consequential half in the dark. 

At FFCC, we spend a lot of time listening to people talk about food — in citizens’ dialogues, in village halls, around kitchen tables. They are not, by and large, demanding that the state ban things. What they ask for is a level playing field, with clear rules. The hidden lobbying budget is exactly the thing that makes them lose faith. You cannot persuade people the system is fair while keeping the real rules secret.  

The remedy is not complicated, nor should it be controversial. A lobbying register worth the name would record who is lobbying whom, on whose behalf, about what, and for roughly how much — including the work done with officials and advisers, not only ministers. That is close to what the Americans have had since the 1990s. It would reveal nothing about any single conversation and everything about the scale of the problem: who is spending their cash, on which questions, at which moments. For a government that says it wants to rebuild trust, it is a helpfully cheap place to start. 

We’re all – policy makers included – allowing ourselves to be distracted by what the food industry chooses to show us. We have spent years arguing about adverts while the big money is operating in a whole new medium. The next time someone assures you the system is working, ask for the figure. The telling thing is that they won’t be able to give it to you — and that is the problem worth fixing.