Barry Delaney, ex-owner of an advertising agency and now industry consultant, is still shocked by the UK ban on tobacco advertising, brought in on Valentine's Day last year. “I really didn't think it would happen in my lifetime,” he says, despite being one of the first industry figures to oppose cigarette advertising.

First smoking, then junk food: now advertising executives are wondering where public health campaigners will strike next

Credit: STUART HIGGINS/REX

But happen it did, and its effect is still reverberating. The victory has given campaigners the confidence to carry the fight over into other products that pose a threat to public health—notably junk food, alcohol, and cars.

Although no one will admit it publicly, reports suggest that concern is growing among advertising agency executives that the industry could be slapped with another statutory ban, this time on TV advertising of unhealthy food for children. The report on obesity of the House of Commons Select Committee on Health, published in May, stopped short of demanding an immediate ban on advertising targeted at children. But it said the food and advertising industries should be given three years' grace to change their policies.

At the same time, alcohol as well as fatty foods is regularly …