Child sugar consumption is storing up a mountain of health problems

Closer to home, only after decades of powerful evidence about the harmful effects of smoking was action taken - advertising banned, taxes increased, smoking in public places stopped, and, only this year, plain packaging approved and smoking with children in cars banned. The tobacco companies still form a powerful lobby and change has been glacially slow. Finally, though, we are seeing a real cultural change, with the take-up of smoking among children slowing.

We are, I think, at the cusp of change on dietary sugar. Again, we have a powerful lobby of the sugar manufacturers and the food industry generally, so progress has been slow. David Cameron is reported to have ruled out a sugar tax without fully considering the evidence - but slowly, very slowly, the tide is turning. However, it is important that the tide turns more quickly than it did for smoking, for a simple reason.