British trader Navinder Singh Sarao outside Westminster Magistrates’ Court, London, in August 2015, after he was granted bail on charges of helping trigger a multibillion-dollar US stock market flash crash. Photograph: Dominic Lipinski/PA Wire

It took Navinder Singh Sarao a long time to accept that he might have been scammed out of $50 million. Stuck in London’s Wandsworth prison, wracked w(...)

The sun sets on the address where Nav Sarao Futures Limited is registered, in Hounslow, London April 21, 2015. Navinder Singh Sarao, a high-frequency trader, was arrested in the United Kingdom over charges he manipulated the futures market and played a role in sparking the May 2010 “flash crash”, the US Justice Department said on Tuesday. Through his company Nav Sarao Futures Limited Plc, Sarao profited to the tune of $40 million, the CFTC said, adding that his alleged manipulation stretched over the period from 2010 to 2014 and continued at least through early April of this year. (Photograph: Neil Hall/Reuters)

From a modest stucco house in suburban west London, where jetliners roar overhead on their approach to Heathrow Airport, a small-time trader was abou(...)