Purple tomatoes: Could GM crop be food of the future?
24 January 2014 Last updated at 22:54 GMT
Scientists in Norwich have developed a genetically modified purple tomato, which is being produced in Canada due to European hostility to GM foods.
Their dark pigment potentially offers the same health benefits as fruit such as blueberries and could be used in everything from ketchup to pizza topping.
David Shukman reports.