A top banking regulator has told MPs that Barclays had a "culture of gaming" and its problems came from "the tone at the top" from former boss Bob Diamond.
Andrew Bailey, head of the Prudential Business Unit at the Financial Services Authority (FSA), added that Mr Diamond's account of his and the bank's relationship with regulators was "highly selective".
Mr Bailey told the Treasury Select Committee, which was taking evidence on the Libor-fixing scandal, that there "was a problem with the institution and that came from the tone at the top", meaning Mr Diamond.
Earlier, former Barclays chief operating officer Jerry del Missier confirmed he had told the bank's money market desk to lower Libor submissions in October 2008 because he believed the Bank of England had directly instructed the bank to do so.
He also revealed that Barclays' compliance department, which is responsible for ensuring that policies and procedures are adhered to, was made aware of the request to lower Libor submissions.
Later in the session, FSA executive chairman Lord Adair Turner said Mr Diamond was aware that the regulator had sent a letter detailing issues with Barclays' culture, contradicting his evidence.
Mr Diamond told the committee he was not aware that the FSA had sent a letter to the bank in April warning over the bank's "aggressive" stance on regulation.
However, an April letter from Lord Turner to Barclays chairman Marcus Agius, who will step down once a replacement for Mr Diamond is found, was subsequently made public.
Lord Turner said that Mr Diamond knew of the letter and had asked to discuss it after a meeting.
Lord Turner added that Mr Diamond had said: "I'm extremely concerned to receive this letter and we take very seriously what you said."