Ancient British warriors showed they were prepared to dye for their country in battles against the Romans by covering themselves in a weed called woad. Now woad, or isatis tinctoria may form the basis for indigo ink in bubble jet printers. According to the Daily Telegraph, the Ministry of Agriculture and commercial companies have put 700,000 pounds into a Bristol University project to make commercial dye from woad. It would provide a renewable resource and a valuable new income for farmers.