A rogue trader who brought a renowned City finance house to its knees in 90 minutes of "disastrous" dealing was last week jailed.

Southwark Crown Court heard how debt-ridden Stephen Humphries, of Percival Road, Feltham, exceeded his personal limits at Sussex Futures Limited by more than a hundred times, and more than double the limits of the company itself, dealing in the gilt futures market.

The 25-year-old lost £750,000 by risking ever increasing amounts like a "desperate gambler."

As a result of Humphries' actions, twenty traders lost their jobs and owner John Sussex eventually went to the wall.

The court heard that Humphries had paid a monthly fee and a commission to his employer and rented a computer terminal to trade in gilts through his company SPH Futures.

On August 6 last year, as Humphries was trading, it was announced American interest rates were likely to be raised which would cause the value of fixed interest investments such as gilts to fall.

Although he was allowed to trade on condition he held no more than ten "lots" or contracts, the court heard that by the time the defendant's actions were discovered and he fled the office, Humphries had acquired 1,129 lots which cost the company a trading liability of £729,239.

Martin Hicks, prosecuting, said: "During a period of one hour, 32 minutes, the company's hard-earned reputation and value was destroyed at a stroke."

Humphries was jailed for three years and nine months after admitting a charge of fraudulent trading.

The court heard that 18 months before his downfall, Humphries had married and fathered two sons.

But then he started to lose money as a trader with his previous company.

With the strain of work finally leading to the break up of his family. Humphries joined Sussex Futures after borrowing his father's life savings and living on his credit card balance.