The building is home to Futex, one of several so-called “trading farms” in the UK that give training, office space and equipment to people prepared to make short-term trades, mostly within a day, with their own money in the hope of being hired or sponsored for a cut of their profits. Navinder Singh Sarao – who has been accused by U.S. authorities of contributing to the May 2010 “flash crash” in Wall Street – worked there between early 2003 and early 2008, according to a statement by Futex on Friday.