Nine major charities urged the European Commission on Tuesday to scrap a science advisor position it says puts too much power over sensitive policy into the hands of one person.

The position of Chief Scientific Advisor was created in 2011 by Commission head Jose Manuel Barroso and given to Professor Anne Glover, a British biologist who activists accuse of backing the cultivation of genetically modified food crops, a hugely controversial practice in key EU member states.

In an open letter to Jean-Claude Juncker, who replaces Barroso in November, the groups criticised the post as "fundamentally problematic as it concentrates too much influence in one person, and undermines in-depth scientific research and assessments carried out by or for the Commission directorates in the course of policy elaboration".

The fight over the development of GM is one of the fiercest debates in the European Union, pitting environmentalists and backers of small-scale farming against the international agri-business lobby that defends the technology as a way to boost crop yields and create rural jobs.

Signatories to the letter included Greenpeace, Friends of the Earth, the Health & Environment Alliance and the Alliance for Cancer Prevention.

Some of these groups have also been critical of the Commission's stance on biofuels and shale gas extraction.

In the letter, the groups warned that re-appointing a science advisor "is not the way for the Commission to ensure that scientific evidence informs its policymaking; rather it creates additional problems".

"Vested interests have long realised that the more you concentrate scientific advice into the hands of one person, the easier it is to control," it added.

In May, European business lobbyists came out strongly in favour of Professor Glover and maintaining the position.

"We see the CSA as a key proponent in science-based decision-making to make the important role of science more visible in the EU institution," BusinessEurope said in a letter to Barroso.

Since taking office, Glover has rarely spoken publically in order, she has said, to remain out of the political fray and continue to hold potentially challenging positions on sensitive issues.