Shaker

"The s" was the name given to an extra-dimensional species encountered by the British military during World War II. They made a deal with the British: the Shakers would be prepared to destroy any Germans that occupied Great Britain, and in return, after the war, the Shakers would be given India. However, the British instead trapped the Shakers, who, several years after the war, escaped and began killing people in London, under the mistaken idea that they were the enemy. They were told by Max Wheeler that the war was over, but when they learned from the First Doctor that the British never intended to honour the deal, they tried to kill everyone, only to be stopped by the Doctor, Max, Susan and Maxine. (PROSE: Losing the Audience)