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* Five ex-bankers involved in third Libor trial
* All deny skewing key rate for personal gain (Adds detail from cross-examination from paragraph 14)
By Kirstin Ridley
LONDON, May 18 (Reuters) - A former Barclays traderaccused of conspiring to rig a global interest rate said apromise to name a colleague in a book and to invite him to hisbar in return for help in setting Libor was "just banter".
Greek-born Stylianos Contogoulas told Southwark Crown Courton Wednesday that he had been instructed by his boss within daysof joining the Barclays dollar desk in 2005 to tell a seniorcolleague the level he wanted Libor rates set at.
"It was done very openly and in a very normal way and gavethe impression this was a regular, normal thing," Contogoulassaid on his first day in the witness box.
Contogoulas, 44, is one of five former Barclays bankerscharged with conspiracy to defraud by manipulating Libor, theLondon interbank offered rate, a benchmark for rates on around$450 trillion of financial contracts worldwide.
He and former colleagues Jonathan Mathew, Jay Merchant, AlexPabon and Ryan Reich all deny dishonestly skewing rates -designed to reflect bank borrowing costs - to favour tradingpositions between June 2005 and September 2007.
As the second defendant to testify in the criminal trial,Contogoulas told the jury that he had been given no impressionthat asking for Libor rates was wrong or dishonest, that he hadnever had appropriate training, had not sought to conceal suchrequests and knew Barclays monitored communications.
In an email exchange on March 13, 2006, Contogoulas toldsenior London submitter Peter Johnson: "Remember when I retireand write a book about this business your name will be writtenin golden letters...and you'll have an open invitation to my barin the Greek Islands he he"
Johnson responded: "I would prefer this not to be in anybooks!"
Contogoulas said during his testimony on Wednesday that thiswas all "just banter, not serious".
"Did anyone ever comment on your emailed requests to(Libor)submitters?" asked his lawyer John Ryder.
"No," said Contogoulas, adding that he spent just minuteseach day doing so and received no personal advantage from doingso.
Johnson's lawyer declined to comment on Wednesday.
Contogoulas, who passed on Libor requests from more seniorNew York traders to submitters in London, said he stopped makingverbal requests and started emailing them because U.S.colleagues might otherwise question whether he was passing theirrequests on.
Emma Deacon, counsel for the Serious Fraud Office (SFO)prosecuting the case, questioned whether Contogoulas wasminimising his role by presenting himself as a conduit from NewYork to London, while in fact he traded the Barclays dollar bookeach morning.
"You're not seeking to minimise it (your role in the Liborrequests)?" Deacon said.
"No," Contogoulas replied.
"You were just a conduit?"
"Yes," he said.
Contogoulas said the volume of his trades amounted toperhaps five percent of Barclays' whole short-end dollar bookand his main role was as a "babysitter" while the New York deskwas closed.
Contogoulas's evidence follows that of Mathew, a formerLibor submitter, who has told the court he had been taught byJohnson to adjust rates to suit traders and only realised thiswas wrong when interviewed by Barclays' lawyers in September2009.
Mathew said he initially lied when U.S. authorities, whokickstarted a global Libor investigation in 2008, quizzed him in2010 because he was afraid of his boss Johnson and of losing hisjob. He only told the truth when U.S. prosecutors offered him anon-prosecution agreement in 2011, he said.
The jury was told last week that Johnson, who had beencharged alongside the other five defendants, pleaded guilty in2014. The third Libor trial brought by the SFO in London isscheduled to last 12 weeks. (Editing by Alexander Smith)
