Tom Sutcliffe: Let's be clear about what we're eating

It hasn't really been a good few days for this Government, when it comes to the relationship between simple scientific facts and public health. Their commitment to giving the people the facts doesn't apparently extend to giving them facts that might contradict current political orthodoxies. But they do have a modest opportunity this week to show themselves to be on the side of useful scientific intelligence. Tomorrow, the House of Commons debates a 10-Minute Rule Bill put forward by the Labour MP Helen Southworth, in which she calls for a legal requirement for a uniform system of food labelling on the front of packaged food.

The words "requirement" and "uniform" are the critical bits here. Lots of companies already label their food, after all – with companies such as the Co-op taking a real lead in letting their customers know exactly what they're putting into their stomachs and, by extension, on to their waistlines and artery walls. The problem is that it isn't compulsory and there are a lot of different ways of doing it. Some companies adopt the Food Standards Authority's preferred system of traffic-light symbols, which alerts shoppers to an excess of saturated fat or sugar, say, with a dot of red or a warning blob of amber.

This has the advantage of simplicity. If you pick up a packet that has four red dots across the front (most systems identify quantitities of sugar, fat, saturated fat and salt) then you know that your indulgence may come with a cost. Unfortunately, it also has the disadvantage – for food processing companies – that it makes people more reluctant to stuff themselves with crap. "Red signals are often misunderstood as 'avoid eating the product'," remarked one opponent.

Can't quite see where the misunderstanding lies there. That's the idea surely – though I can see that you might prefer another system if you're the person selling the product.

There is another system, as it happens, one which uses Guideline Daily Amounts. For the numerate, this could be argued to be more useful still, since, without any alarming hazard lights, it lets you tally up exactly how much of your recommended daily maximum of saturated fat you're going to use up with that little mid-morning treat.

The disadvantage is that you have to look at the small print and do some sums about percentages of percentages if you're not planning to eat the whole pack. Which is, of course, an advantage for companies who don't want you to think too closely about what you're ingesting.

To think that these things only act on customers seems to me a mistake, though – and it's one of the reasons why the traffic light system seems a better bet than the notionally more sophisticated GDAs – and should be enforced by law. Introducing her Bill last year, Ms Southworth quoted a Which? investigation of ready-meals and processed food which discovered that some pizzas had seven times as much salt as a comparable product, and that choosing one brand of lasagne rather than another could multiply your fat intake by five.

Shouldn't the unhealthier choices have a hazard warning on them? And wouldn't it be likely that food producers might change their habits and lifestyles if they were shamed by those embarrassing red blotches? In fact there is plenty of evidence that the traffic light system helps prevent the excess sugar and salt getting into the food in the first place – perhaps a more reliable way of improving the national diet than relying on customers self-restraint.

Ten-Minute Rule Bills usually get nowhere. They're just a megaphone. But this one deserves a bit of a shove from the Government.

A marriage that might turn out to be a piece of performance art

I'll believe in Sam Taylor-Wood's marriage to Aaron Johnson when the confetti actually hits the pavement. Until then it strikes me as just too good a practical joke – and too good a publicity magnet for the film on which they met – to be entirely trustworthy. I can't suppress the feeling that the whole thing, fully documented with red-carpet shots and subsequent media commentary, might turn up in next year's Turner Prize exhibition, as an installation exploring gender and generational attitudes.

And if it is true, the problem surely isn't the relationship – they are both consenting adults – but the marriage. It's easy enough to see why both parties might have got a bit carried away (the terms "hot young thing" and "wealthy achiever" should no longer carry gender assumptions). But the idea that you can freeze such a mutual infatuation with a ceremony and fix it in place for another 40 years (one presumes they're in for the long haul) is so dizzyingly childish as to undermine both parties' claims to be over the age of discretion.

As an admirer of Taylor-Wood's work, I'm hoping for a tongue-in-cheek explanation rather than a head-over-heels one.

What's this got to do with protecting children?

I WOULD like to know a bit more about the 98,000 "unsuitable people" the Government claims have been prevented from working with children by the Criminal Records Bureau over the past five years. You hear this figure dutifully trotted out every time the new vetting and barring scheme comes under pressure, the buried implication being that opponents of the scheme are ready to unleash 20,000 paedophiles a year on Britain's children.

What exactly does "unsuitable" mean though? One newspaper reported that a parent had been barred from assisting a scout group because of a teenage conviction for stealing sweets. How many similar cases are there in that impressively large figure? And doesn't the statistic have to be set alongside a smaller number which gets much less publicity – the number of CRB-cleared people who go on to commit abuse.

This year alone, a taxi driver for Camden schools was found guilty of assaulting a child, despite multiple convictions for abuse in an overseas court (and a CRB clearance). And Vanessa George (found guilty of child abuse in the nursery photographs case) and Tracy Lyons (currently charged in connection with the same case) had both been given CRB clearance. Exactly whose safety was protected by their certificates? Only that of their employers, I would suggest, who can now legitimately claim they did all that was required of them.

You might (grudgingly) trade the corrosion of trust and bureaucratisation of common sense the new scheme will involve if you could be persuaded it would increase children's safety. But it seems a lousy swap when it probably won't.