The ex-employee of Thomson Reuters, who asked to remain anonymous, told the BBC that the BBA was told regularly about the implausible rate submissions of several banks involved in the process.
The BBA confirmed it had received reports from Thomson Reuters about rates that fell “outside normal tolerances”, but it said the warnings did not imply wrongdoing.
Barclays was recently fined £290m by the Financial Services Authority and the US Commodities Futures Trading Commission (CFTC) for manipulation of the LIBOR rate between 2005 and 2009. Other banks are now being investigated.
The former member of the rate-compilation team told the BBC that John Ewan, head of LIBOR at the BBA, was given weekly reports detailing oddities identified by Thomson Reuters.
“He [Ewan] was the watch-keeper at the time,” the rate-compiler said. “We would tell him of our concerns.
“I wouldn’t say he took no action. He took notice of them. Action was taken. But the BBA was not very effectual at the time.”
During 2008, the BBA initiated a review of the Libor-setting process. It said this was partly down to the information supplied to it by the BBA. But it said it was “at no time aware” that rates were being manipulated.
