July 14 (Bloomberg) -- Three ex-British bankers pleaded not guilty to fraud charges related to a deal with bankrupt energy trader Enron Corp. after losing a three-year extradition fight. David Bermingham, Giles Darby and Gary Mulgrew, extradited from the U.K. yesterday, are accused of bilking their former employer Royal Bank of Scotland Group Plc's Greenwich NatWest unit out of millions of dollars from the sale of an Enron off- the-books partnership. A bail hearing has been scheduled for July 21 in Houston federal court, where they entered their pleas. U.S. Magistrate Judge Stephen Smith released the men into the custody of one of their lawyers, Houston attorney Dan Cogdell, until the hearing. Smith accepted the $100,000 offered by both Bermingham and Darby and the $20,000 offered by Mulgrew to secure their temporary release.