The misuse of science by campaign groups to promote their cause is all around us. But it has not gone unnoticed. Debates about the weight of evidence for or against scientific topics such as climate change, homeopathy or the safety of vaccinations are widespread. See for example the excellent column and blog by Guardian writer Ben Goldacre on ‘bad science’. This week, Goldacre points out that ‘as long as you cherry pick the data and keep one eye half closed, you can prove anything with science’.

But what happens when the objectives of groups campaigning on different themes are in conflict. This is the messy situation highlighted in a recent Political Update from the British Union for the Abolition of Vivisection (BUAV). The Update complains about a Greenpeace commissioned study which has concluded that a strain of genetically modified (GM) maize, approved for sale by the European commission, has shown signs of toxicity in laboratory rats. Greenpeace is claiming that such GM food poses significant health risks, but the BUAV responds that this study demonstrates little more than the supposed limitations of animal tests.

Both parties are guilty of distorting science by simply interpreting evidence as they wish to see it.

The briefing by Greenpeace is certainly confusing. It is difficult to distinguish the science from the claims of Greenpeace, who say this new scientific evaluation shows that the GM maize ‘should not have been approved in the EU or elsewhere’. But the abstract of the paper itself only states that ’it cannot be concluded that [this variety of GM maize] is a safe product’.

Predictably, the BUAV claims that the animal data simply ‘raise more questions than they answer’. Of course, as we have pointed out many times, there is no guarantee of perfect extrapolation to humans in every case of animal toxicity studies. Nonetheless, they give valuable information to be taken into account for regulatory decision-making. BUAV is guilty of deliberately confusing the scientific evidence with the risk evaluation process, which is a political judgement based on the best scientific data available.

It’s also been stressed many times before that impartial, evidence-based science advice is but one element of political decision-making. The evidence also shows that animal studies have proved invaluable in helping to protect people from hazardous chemicals.