Sarao, 36, who traded from his parents' modest home in west London, has been charged by the U.S. Justice Department with wire fraud, commodities fraud and market manipulation over a period of several years but told a hearing last week he would fight extradition.

He was granted bail provided he produced a surety of just over 5 million pounds and met other conditions, but an official at London's Westminster Magistrates' court said on Tuesday he had been unable to raise the cash and would return for a "lack of surety hearing".

"If they haven't paid they come back every week," the official said. "He's not paid as yet."

(Reporting by Michael Holden; editing by Stephen Addison)