The food industry was yesterday given until next year to curb marketing of fatty and sugary products to children, if it is to avoid advertising bans or new labelling laws.
The threat, from the European Commission, reflects mounting concern over the rise in obesity among young people increasingly vulnerable to the twin dangers of a junk food diet and lack of exercise.
No specific plans have been drawn up, but his threat could ultimately mean campaigns featuring Ronald McDonald or the Honey Monster being banished from the airwaves.
More likely is an effort to force companies to label their products clearly or introducing guidance such as Britain's traffic light scheme to highlight healthy eating
The European health commissioner, Markos Kyprianou, said: "We used to regard obesity as only an American problem. Today obesity is on the rise in Europe, especially among children. I am concerned that advertising of foods high in fat, sugar and salt should not target vulnerable consumers like children."
The commissioner said he would wait until next year before proposing legislation to force companies to improve their performance. He argued: "We have to protect children from marketing because they are vulnerable, but at the same time we have to promote accurate information to all consumers so they can exercise their judgement."
The ultimatum underlines the seriousness of a child obesity problem which now afflicts Mediterranean countries as much as the north of Europe.
In Italy, Spain, Greece and Malta around one in three 10-year-olds are categorised as either overweight or obese - higher than the UK's figure of 22 per cent. Experts believe that young people in southern countries now have access to the same junk food as their counterparts to the north and suffer from the same problem of lack of exercise. In countries where food shortages were experienced in the past, adults sometimes encourage their children or grandchildren to eat more than they need.
EU officials are due to meet with a committee drawn from industry, consumer and health groups today to discuss moves for voluntary action. Mr Kyprianou hopes that plans emerging from this "round table" will be sufficient for him to avoid the need to legislate.
The commissioner's initiative was backed by the UK's minister for public health, Melanie Johnson, who said: "We are pleased to see he has signed up so clearly to our agenda on this issue. There is a strong case for action to limit the advertising and promotion to children of those foods that are high in fat, salt and sugar."
The European Commission could act by drawing up new proposals for a revised nutrition labelling laws across the 25 member states.
However a spokesman for Viviane Reding, the commissioner responsible for the media, played down the prospects of an EU-wide ban against advertising to children. He said: "It is not under discussion at the moment. I could not rule it out but this is not the direction that seems to be emerging."
Beate Kettlitz, food safety adviser for the European consumers' organisation Bureau Européen des Unions de Consommateurs (Beuc), said: "Nutrition was never high on the political agenda. Now it is climbing but it needs to be discussed across the range of policy areas."
Policies to improve nutrition andawareness of ingredients should be coupled with efforts to encourage young people to take more exercise, she added.