Or so the British suspected, for many years. According to wikipedia:
"The tomato plant was not grown in England until the 1590s . . . . One of the earliest cultivators was John Gerard, a barber-surgeon. Gerard's Herbal, published in 1597 and largely plagiarized from continental sources, is also one of the earliest discussions of the tomato in England.
"Gerard knew that the tomato was eaten in both Spain and Italy. Nonetheless, he believed that it was poisonous (tomato leaves and stems contain poisonous glycoalkaloids, but the fruit is safe). Gerard's views were influential, and the tomato was considered unfit for eating (though not necessarily poisonous) for many years in Britain and its North American colonies."
Coming from the land whose culinary heritage reached its height with such dishes as steak and kidney pie, I can't say I'm the least bit surprised. But we do owe the Brits for popularizing the marvelous ritual of afternoon tea (although it is increasingly enjoyed by mostly tourists and elderly women).