TO answer Dennis Barton’s question regarding GM crops, it is not true that all GM crops by definition sterile; the problem is that some agricultural biotechnology companies have chosen to develop Gene Use Restriction Technology, GRUT, that renders plants sterile.

The problem started in the 1980s when the World Bank agreed a seed policy that required nations such as India to de-regulate the seed sector. Companies such as Monsanto quickly took advantage, reaching agreements that locked farmers into deals that benefited companies not farmers.

Monsanto, which controls 95 per cent of all cotton produced in India, patented seeds which had previously been the farmers’ common resource and started demanding royalties. A free and renewable resource became a sterile patented commodity. This has created a debt trap and forced farmers across India into debt, destitution and suicide.

Genetically modifying crops is not by definition evil, humans have manipulated the genes of plants for millennia, but lax global regulation has enabled multinational corporations to operate without restriction.

The Convention on Biological Diveristy has banned GRUT, but the damage has been done and millions are suffering. A key author on this is Vandana Shiva, who has produced hundreds of scientific papers on these issues.

Christian Vassie, Blake Court, Wheldrake, York