Professor John Pickett's research into GM crops was at the centre of a public debate last month.
His experimental work has engineered insect alarm systems into wheat, so that the plants give off chemicals which repel greenflies or aphids.

Activists known as "Take the Flour Back" had threatened to destroy field trials, but the day passed peacefully.

Professor Pickett's research for over 30 years has been based on using insect pheromones (the chemical messengers the insects send to one another) and understanding how plants are able to attract or push crop pests away. A pioneering technique he's developed known as push pull means that farmers in Africa have been able to improve their yields simply by planting what are known as companion crops that repel pests and trap crops which entice the insects. So if this approach is so successful is there really a need for GM versions?