Under a public-private partnership deal, the charity stands to make millions of pounds by lending both its name and resources to McDonald's World Children's Day event, which will be rolled out in the burger firm's restaurants in 121 countries on November 20 this year.

The promotion, which aims to raise money for McDonald's charitable arm and a dozen Unicef programmes, includes a pop concert in China, which will be broadcast over the internet - access to which can only be obtained by buying a Big Mac burger. Unicef will receive a cut of the profits from each Big Mac sold.

In the US, 20m Unicef "trick or treat" charity collection boxes used by children to collect money on Halloween night will be distributed through McDonald's outlets. In Hong Kong, a joint promotion called "Love for our future with Unicef" is being planned, with the charity benefiting from the sales of specially-designed postcards available in restaurants.

Unicef claims that apart from benefiting financially, the campaign will help raise the profile of both the charity and wider child health issues. In the US, it hopes to "reach a whole new generation of children whose parents supported Unicef when they were kids".

But public health specialists across the world have criticised the charity's involvement with McDonald's, arguing that the partnership could damage the credibility of its work on child health, nutrition and education, particularly in the third world.

This week a letter sent to Unicef's executive director Carol Bellamy from more than 50 doctors, academics and activists argues that the World Children's Day partnership runs counter to the charity's role in promoting good nutrition to the world's children.

It states: "McDonald's is a global leader in the marketing of junk food that is creating soaring rates of childhood obesity and type 2 diabetes, and that is disrupting traditional ways of food preparation in families and cultures. It is truly a challenge to see how this partnership with McDonald's is consistent with Unicef's claim to promote 'good nutrition' to the world's children.

"As you know, McDonald's markets precisely the high-added-fat, high-added-sugar junk food that undermines good nutrition for the world's children."

Unicef's New York office said last night said that the partnership did not mean that Unicef endorses McDonald's or its products. But a spokeswoman admitted that the charity was aware of the concern expressed by the public health community and was "watching the public response closely".

Unicef is signed up to co-promote World Children's Day in Australia, Brazil, China, Denmark, France, Hong Kong, Japan, Mexico, New Zealand and the US. The UK committee of Unicef said it would not be involved with events held by the burger chain.

In a speech in May, UN secretary general Kofi Annan called for the private sector to become more involved in UN efforts to help children, arguing that "public-private partnerships have the power to help children in many ways".

Geof Rayner, chairman of the UK Public Health Alliance, said: "Unicef needs the money and McDonald's can deliver it. There's nothing wrong with corporate social responsibility in principle, but there's a question of whether the dividing line into irresponsibility has now been crossed."

Professor Tim Lang, professor of food policy at Thames Valley University and a UN consultant, told SocietyGuardian.co.uk: "It is a sad, sad day if the UN's children and health charity is reduced to taking sponsorship from a fast food company. Why should we accept that Unicef has any credibility left?"

Jeanette Longfield, coordinator of the charity Sustain, the alliance for better food and farming, said: "McDonald's is the flagship for junk food, aggressively targeted at children. Does Unicef think that this is an appropriate partnership?"

McDonald's World Children's Day coincides with the anniversary of the UN's adoption of the Convention of the Rights of the Child in November 1989.

Sent to Carol Bellamy, executive director of the United Nations' children's charity, Unicef

Saturday August 3, 2002 The Guardian

Dear Ms Bellamy:

On July 19, Unicef announced its partnership with the McDonald's Corporation to hold "McDonald's World Children's Day".

In effect, Unicef is lending its good name and endorsement to McDonald's, the world's largest fast food chain. McDonald's is a global leader in the marketing of junk food that is creating soaring rates of childhood obesity and type 2 diabetes, and that is disrupting traditional ways of food preparation in families and cultures.

It is truly a challenge to see how this partnership with McDonald's is consistent with Unicef's claim to promote "good nutrition" to the world's children. As you know, McDonald's markets precisely the high-added-fat, high-added-sugar junk food that undermines good nutrition for the world's children.

McDonald's is responsible for multimillion dollar ad campaigns that prod children to nag, whine and throw tantrums so that their parents will consent to buy them junk food. The company's ad campaigns deliberately foment conflict between parents and children regarding food.

It is not the proper role of Unicef to endorse or serve as enabler for corporate activities of this kind. Do you really think people contribute to Unicef so that you can help corporate advertisers to manipulate innocent and impressionable children with sophisticated psychological techniques, cause strife in the home and promote the consumption of junk food?

Unicef's mission is to protect children from just these things. Therefore, we urge you to reconsider your partnership with the McDonald's Corporation, and cancel "McDonald's World Children's Day" immediately.

Sincerely,

• Enola Aird, director, the Motherhood Project, Institute for American Values
• Monika Arora, programme director, HRIDAY-SHAN, India
• The Honorable Danielle Auroi, member, European parliament, France
• Belen Balanya, co-author, Europe, Inc.: Regional and Global Restructuring and the Rise of Corporate Power
• Peter Barnes, co-founder, Working Assets; author, Who Owns the Sky?
• Medea Benjamin, founding director, Global Exchange
• Stephen Bezruchka MD, MPH, senior lecturer, department of health services, school of public health and community medicine, Washington University
• Louis Borgenicht MD, member, board of directors, Physicians for Social Responsibility
• Brita Butler-Wall PhD, executive director, Citizens' Campaign for Commercial-Free Schools
• Nancy Carlsson-Paige EdD, professor of child development, Lesley University
• Vittorio Carreri, presidente, Giunta esecutiva, SItI; head of the sanitary prevention unit of Lombardy Region
• Joan Claybrook, president, Public Citizen
• The Honorable Ian Cohen MLC, New South Wales parliament, Australia
• Ronnie Cummins, national director, Organic Consumers Association
• Donald R Davis PhD, research associate in nutrition, biochemical institute, Texas University
• Erica Frank MD, MPH, vice-chairwoman and associate professor; director, preventive medicine residency program, department of family and preventive medicine, Emory University school of medicine
• Gary Goldbaum MD, MPH, associate professor of epidemiology, Washington University
• Joan Gussow EdD, M S Rose professor emeritus, nutrition and education, teachers college, Columbia University
• Andy Harris MD, board of directors, Physicians For Social Responsibility
• Paul Hawken, Natural Capital Institute
• Michael F Jacobson PhD, executive director, center for science in the public interest
• David L Katz MD, MPH, FACPM, associate clinical professor, Yale school of medicine
• Joe Kelly, executive director, Dads and Daughters; and publisher, Daughters Newsletter: For Parents of Girls
• Michael Kieschnick, president, Working Assets
• Jean Kilbourne, author, Can't Buy Me Love: How Advertising Changes the Way We Think And Feel
• Ronald M Krauss, MD, senior scientist, life sciences division, Lawrence Berkeley national laboratory; adjunct professor, department of nutritional sciences, University of California, Berkeley
• Velma LaPoint PhD, associate professor of human development, Howard University
• Pieta-Rae Laut, executive director, Public Health Association of Austrailia
• Diane Levin PhD, professor of education, Wheelock College
• Jane Levine EdD, founder, Kids Can Make A Difference
• Lida Lhotska PhD, regional coordinator for Europe, International Baby Food Action Network
• Susan Linn EdD, associate director, media center of the Judge Baker children's center; instructor in psychiatry, Harvard Medical School
• Alison Linnecar, international coordinator, Geneva Infant Feeding Association
• Alan H Lockwood MD, professor of neurology and nuclear medicine, University at Buffalo; past-president and chairman, environment and health committee, physicians for social responsibility
• Ben Manski, co-chairman, Green Party of the United States
• Mohamed Marwoun MS, specialist, community medicine, ministry of public health, Saudi Arabia
• Bob McCannon, executive director, New Mexico media literacy project
• Robert McChesney PhD, research professor, institute of communications research, University of Illinois at Urbana-Champaign; author, Rich Media, Poor Democracy
• Mary Anne Mercer DrPH, senior lecturer, Washington University school of public health and community medicine
• Jim Metrock, president, Obligation, Inc.
• Mark Crispin Miller PhD, professor of media ecology, New York University
• Diane M Morrison PhD, research professor & associate dean for research, Washington University school of social work
• Keven Mosley-Koehler MS, MPH, grant project manager, Group Health Community Foundation
• Robert K Musil PhD, MPH, executive director and CEO, Physicians for Social Responsibility
• Peggy O'Mara, editor and publisher, Mothering Magazine
• Sheldon Rampton, editor, PR Watch
• Mike Rayner DPhil, director, British Heart Foundation health promotion research group
• John Rensenbrink, US representative, Global Green Network
• The Honorable Lee Rhiannon MLC, New South Wales parliament, Australia
• Gary Ruskin, executive director, Commercial Alert
• Ted Schettler MD, MPH, science director, Science and Environmental Health Network
• Juliet Schor, professor of sociology, Boston College; author, The Overspent American and The Overworked American
• John Stauber, executive director, Center for Media & Democracy; co-author, Trust Us, We're Experts and Toxic Sludge is Good for You
• Vic Strasburger MD, professor of pediatrics, University of New Mexico school of medicine; author, Children, Adolescents, and the Media
• Karen Valenzuela MA, MPA, Washington state public health association
• Susan Villani MD, medical director, schools programs, Kennedy Krieger Institute; assistant professor of psychiatry, Johns Hopkins school of medicine
• Robert Weissman, co-author, Corporate Predators; co-director, Essential Action
• The Honorable Matti Wuori, member, European parliament, Finland