New documents from the Wikileaks whistle-blowing website suggest the US lobbied hard to get the EU to soften its anti-GM stance and was even prepared to risk a 'trade war'.

Leaked diplomatic cables suggest Paris-based US ambassador Craig Stapleton called for a 'retaliation list' of EU countries unsupportive of GM to be drawn up after the French government stopped the marketing of a GM corn variety from US company Monsanto in 2007.

Cables from 2009 also reveal US efforts directed at the Vatican to get church officials to speak in favour of GM foods.