They look for all the world like a visitor from outer space, or an intergalactic traveller from Star Wars . But the army of robots working in communities around the UK are being hailed as the future of British doorstep deliveries, and the greenest shop from home option to help save planet Earth. It costs as little as 99p to bring shopping to your door, making them popular with the elderly, disabled and children; they play 'Happy Birthday', Merry Christmas songs and even 'I love Rock and Roll'.