Marcus Agius, Barclays’ executive chairman, told the Treasury Select Committee today Diamond had voluntarily chosen to forgo his bonus.
Agius also said he was "truly sorry" and said he felt "ultimately responsible for the reputation of the bank".
Agius resigned when the LIBOR rigging scandal broke but remains in charge until Diamond’s replacement is appointed.
It comes a day after Bank of England would-be governor Paul Tucker denied Diamond’s implication that he had instructed Barclays to manipulate its LIBOR rate submissions in 2008.
Tucker told the TSC members yesterday that Diamond’s account of a phone call between the two men gave “the wrong impression”.
And he added that no government ministers had asked him to “lean on” Barclays to lower its rates.
Tucker said he was not aware of any LIBOR manipulation at the time but now realised the LIBOR market was a "cesspit".
Last week Diamond gave evidence to the TSC and revealed a note he had made of a call with Tucker.
Diamond claimed Tucker said: “It did not always need to be the case that we appeared as high [with LIBOR submissions] as we have recently".
The note also suggested Tucker described concerns among "senior figures within Whitehall" about why Barclays was setting its LIBOR rate at the "top end".
Barclays LIBOR submissions fell days after this conversation.
Last week Diamond defended the drop claiming the rate came down because of a successful capital raising in the Middle East reducing the bank’s funding costs.
He also admitted that Barclays' chief operating officer Jerry del Missier, who resigned last Tuesday, had "misunderstood" Tucker’s comments and consequently ordered traders to lower Barclays' LIBOR rates.
Earlier this month Barclays was fined £290m by UK and American regulators following an investigation into a group of traders who artificially lowered LIBOR and EURIBOR submission rates.
Global regulators continue to investigate up to 15 other banks.
