John Reid, the health secretary, renewed the threat of legislation to ban junk-food commercials if the new codes have not proved effective when the government reviews their impact in 2007.
But he promised the government would work with the two industries to allay public concern about ads targeting children and announced the setting up of a new food-and-drink advertising and promotion forum.
In a progress report on Wednesday on the White Paper on public health issued last November, Reid set out a detailed timetable for implementing curbs on food ads. He said Ofcom would consult this summer on tighter broadcast rules, which are likely to include a 9pm watershed.
At the same time, the new forum would identify how to strengthen the existing codes on press and poster ads. A consultation exercise on this would take place between August and October this year, with the two new codes covering broadcast and non-broadcast commercials adopted early next year.
Ministers will "assess the change to the nature and balance of food advertising" in early 2007 and make a final decision on whether to bring in legislation in mid-2007.
Reid warned the two industries that he was under pressure to go further than the voluntary self-regulation approach he is still pursuing.
He called on broadcasters and advertisers to participate in healthy-living promotions, saying the £743m adspend on food, soft drinks and chain restaurants in 2003 dwarfed a government spend of £7m on healthy-eating campaigns.
Reid also called for a "traffic light" system to identify unhealthy foods.
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