1990: Cotton plants are first genetically engineered to produce enough Bt toxin (derived from the Bacillus thuringiensis bacterium) to be protective against insects

1996: The first Bt cotton varieties, known as Bollgard Cotton in the U.S., are introduced commercially by Monsanto and Delta and Pine Land Company

1997: China begins cultivating Bt cotton, increasing the area of the crop planted to 1.8m hectares worldwide

2003: Large scale field trials of herbicide-tolerant GM crops in Britain show that changes in herbicide use have an impact on weeds and insects that might also affect country wildlife

2009: 49 per cent of cotton production worldwide is Bt cotton — using 16m hectares

2010: Pakistan, the world's fourth largest cotton-grower, becomes the latest country to adopt Monsanto's Bt Cotton

2010: No GM crops are grown commercially in the U.K. Spain is the biggest producer in Europe, but there are also significant amounts of crops grown in France, Germany and the Czech Republic