A landmark victory against the government over pesticide spraying was overturned today, prompting accusations of a "whitewash" from the environmental campaigner who brought the original case.

Georgina Downs, said the decision by the court of appeal to overturn the judgement was "bizarre" and a "public health scandal". She vowed to take the fight to the House of Lords. (Read her full statement here.)

The environment department Defra, which brought the appeal, welcomed the ruling, which it said showed the government had complied with its obligations under European law.

The case turned on how exposure to pesticides sprayed onto fields to boost crop growth may affect peoples' health.

The appeal follows a high court ruling in November that Downs, who runs the UK Pesticides Campaign, had produced "solid evidence" that people exposed to chemicals used to spray crops had suffered harm.

Reacting to the appeal victory, Hilary Benn, environment secretary, said: "In controlling pesticides, the protection of people's health is our priority. That is why we are already working to better assess bystander exposure to pesticides so that we can continue to improve our models."

He added: "In view of the issues raised by Georgina Downs and the new European directive, we will consult this autumn on how to give people access to farmers' spray records, how to give residents prior notification of spraying activity, and what else should be included, for example, monitoring and training."

The original judgment said the government had failed to comply with a European directive designed to protect rural communities from exposure to the toxins. Theruling, from Mr Justice Collins, said the environment department, Defra, needed to reassess its policy and investigate the risks to people who are exposed. Defra had argued that its approach to the regulation and control of pesticides was "reasonable, logical and lawful".

Downs, who lives on the edge of farmland near Chichester, West Sussex, launched her campaign in 2001. She blames repeated exposure to pesticides for persistent ill health.

Responding to today's appeal judgment, she said: "I am upset, but not as upset as if the ruling had gone against me on my own evidence."

Downs claimed the appeal judges ignored the evidence she gathered during her campaign, and instead relied on official reports to reach their findings.

In the new ruling, Lord Justice Sullivan said that Downs "genuinely believes that her own, and her family's health problems have been caused by the exposure to pesticide spraying." But he said that although Downs is "a most effective campaigner" she had no formal scientific or medical qualifications.

Mr Justice Collins's reference to "solid evidence" substituted his own evaluation for that of Defra, said Lord Justice Sullivan.

The appeal judge said the regulatory framework for pesticides required balance between the interests of the individual and the community as a whole.

The Crop Protection Association, which represents the pesticides industry, said the judgment was a victory for common sense. Dominic Dyer, chief executive, said: "Without pesticides to keep weed, pest and disease pressures in check, crop yields would fall by around a third, something we can ill afford at a time of heightened concern about food security and population growth."

Peter Melchett, policy director at the Soil Association, which promotes organic food grown without artificial pesticides, said: "Whatever the court of appeal says, the fact is UK regulation of pesticide spraying does not take into account the safety of schools or families living next to sprayed fields."