A trader fighting extradition over claims he helped cause a 'flash crash' in the US stock market remains in custody.

Navinder Singh Sarao was granted conditional bail at Westminster Magistrates' Court on Wednesday (April 22), having been arrested the previous night at his home in Clairvale Road, Heston.

However, the court confirmed on Friday (April 24) that the 36-year-old - dubbed the 'Hound of Hounslow' has yet to pay the £5m of securities required as a condition of his release, meaning he has been unable to return home.

Mr Sarao is accused by the US government, which is seeking his extradition, of allegedly contributing to the 'flash crash' of May 2010, which wiped £570bn from the US stock market in just five minutes.

The US Department of Justice has charged him with a total of 22 counts of fraud, manipulation and 'spoofing' - the practice of bidding or offering for shares with the intention of cancelling before the transaction can be completed, thus artificially altering share prices.

The charges are reported to carry a maximum jail term of 380 years between them.

US court papers state he earned £585,000 on the day of the crash and nearly £27m over four years by using automated software to 'spoof'.

Neighbours this week recalled playing on the streets as children with Mr Sarao, during the '80s, as they spoke of their shock at his arrest.

Anil Puri said: "It's come as a big surprise. I didn't even know he was involved in trading. We used to play outside together when we were young but we haven't seen him much in recent years.

"He was always friendly when he was young and you could tell he was ambitious even at that age."

Mr Sarao - whose 'Hound' nickname is a comic reference to The Wolf of Wall Street film, starring Leonardo DiCaprio - is due to appear again at Westminster Magistrates' Court on Wednesday (April 29), should he have failed to pay the required securities by then.

A two-day extradition hearing at the court has been set for August 18 and 19.