Jerry Del Missier has told MPs that the decision to lower Libor submissions in the midst of the financial crisis seemed "appropriate".
The Canadian banker said he "fully expected" staff to take into account the views raised by the Bank that the bank's rates were too high.
However, he told the Treasury Select Committee that he only spoke to the head of the money market desk and did not follow up to check what effect his instruction had on Libor submissions.
The chairman of the Financial Services Authority (FSA) will also appear before the Treasury Select Committee to answer questions over Libor.
Lord Adair Turner will be asked about the FSA's involvement and whether it was tough enough when rate rigging occurred between 2005 and 2009.
The former Barclays director who told staff to lower their interest rate submissions is to give evidence to MPs.
Jerry del Missier resigned as the bank's chief operating officer two weeks ago at the same time as Bob Diamond quit as chief executive.
He is appearing before the Treasury Select Committee.
The Prime Minister was asked whether he will call on the Chancellor George Osborne to apologise for allegations he was seen to have made against the Shadow Chancellor Ed Balls over the Libor rate-rigging affair.
He replied that Mr Osborne had said that Mr Balls "had some questions to answer". He continued: "I'm not sure there's anyone in this house who doesn't thing the Shadow Chancellor has some questions to answer".
The Treasury Select Committee has called two witnesses to give evidence on the Libor rate-rigging scandal on Monday:
- Jerry del Missier - former chief operating officer at Barclays
- Andrew Bailey - head of the Prudential Business Unit, FinancialServices Authority
- Lord Turner - Executive Chairman, FinancialServices Authority
Bob Diamond tonight angrily rejected suggestions that he misled MPs over regulators' concerns about activities at Barclays.Read the full story ›
The former Barclays boss Bob Diamond has written a letter to the Treasury Select Committee chairman Andrew Tyrie over claims he misled MPs about regulators' concerns in April over the bank's behaviour.
Having watched the committee's session today I was dismayed that you and some of your fellow committee members appeared to suggest that I was less than candid with the committee last week.
Any such suggestion would be totally unfair and unfounded.
The focus of your concern appears to relate to correspondence between Messrs. Turner [the head of the FSA] and Agius [the Barclays chairman] in April 2012. The questions asked of me, however, concerned the period of promotion in September 2010 and the board meeting I attended in February 2012.
As the letters of April 2012 make clear, those letters followed an April meeting between Messrs. Turner and Agius which I did not attend. I was not asked about the April 2012 meeting nor was I asked about nor shown follow up letter to that April meeting at our session.
[...] The comments made at today's hearing have had a terrible unfair impact upon my reputation, which is of paramount concern to me.
Former Barclays chief executive Bob Diamond's letter to Treasury Select Committee chairman Andrew Tyrie.
He appeared before the committee last week, the day after quitting his post in the wake of the rate-rigging scandal.
Sky News is reporting that former Barclays chief executive Bob Diamond has sent a letter to Treasury Select Committee chairman stating that he was "dismayed" at members of the committee suggesting he was "less candid" after appearing before them last week over the rate-rigging scandal.
The United States' Senate Banking Committee Chairman Tim Johnson has expressed his concerns over the manipulation of Libor rates, following the Barclays bank rate-rigging scandal.
I am concerned by the growing allegations of potential widespread manipulation of Libor and similar interbank rates by some financial firms.
At my direction, the Committee staff has begun to schedule bipartisan briefings with relevant parties to learn more about these allegations and related enforcement actions.
It is important that we understand how any manipulation may impact American consumers and the U.S. financial system.