A British financial trader accused of setting off a "flash crash" in U.S. stocks in 2010 from his London home claims he was just good at his job.

Navinder Singh Sarao, 36, is fighting extradition to the U.S. and appeared at a London court Wednesday.

He failed in a bid to have the payment of a 5 million pound ($7.5 million) security removed from his bail conditions. The sum is equivalent to what he says he has in his trading account.

As he was being led away from the dock he turned to the public gallery and said: "I haven't done anything wrong apart from being good at my job. How is this allowed to go on, man?"

Sarao is accused of manipulating the market and setting off the crash.