Mailsort Three aka (third-class mail) is Royal Mail's mass-mailing service. It offers per-item postage rates far below first and second class mail, but is subject to a minimum spend of £500. EMD has argued that this discriminates against rural areas, with Highland Scotland being arguably the worst affected region in the UK. For example, civic associations in urban areas can economically put a flyer through every letterbox within walking/cycling distance of, say, a community hall. But out in the countryside? Not so much.