Barclays' Libor-rigging transgressions will be "put in perspective" by the fines handed out to other international banks, according to the first direct comments by the UK lender about the scandal's potential impact on the rest of the industry.

In a memo sent to staff yesterday evening and which has been leaked to me, the nine members of the bank's executive committee warned that the Libor crisis should not distract them from the core task of safeguarding Barclays' vast balance sheet.

"The macro-environment remains febrile, especially in Europe. We have to remain vigilant on balance sheet exposures and risk management. In short, our focus must remain on capital, funding and liquidity; improving returns; and driving income growth."

The memo, co-written by Marcus Agius, Barclays' outgoing chairman, apologised for the impact of the rate-fixing episode on the bank's staff, but hinted that its rivals were likely to be hit even harder than the £290m in fines imposed on Barclays.

"As other banks settle with authorities, and their details become public, and various governments' inquiries shed more light, our situation will eventually be put in perspective."

Approximately 15 other lenders, including Lloyds Banking Group and Royal Bank of Scotland, are under investigation by authorities probing a crisis which has also cast doubt on the competence of the Bank of England and Financial Services Authority. A string of inquiries has also been triggered, including one that will examine the business practices and culture of Barclays.

I understand that 90m emails and as many as 1m voicemails will be made available to the independent figure being drafted in to spearhead that probe, the details of which are being finalised this weekend.

"Last week, it was announced that Sir Mike Rake, our Deputy Chairman, would lead an external review of business practices across the bank," yesterday's memo said.

"That review will begin shortly, and the independent reviewer will have access to every resource, and all the co-operation, he or she requires in order to complete the work. This is an important intervention to ensure that appropriate values are applied consistently across Barclays, and the Executive Committee will support and drive implementation."

The executives also used the memo, headed ‘Restoring our reputation, building our business', to reject suggestions that Barclays was examining a full separation of its retail and investment banking operations.

"There has been much speculation in the media about potential changes in our strategy. This is inevitable in a situation such as this – but it is simply speculation. In the face of that, it is important that you hear from us, on behalf of the Board, an unequivocal statement: our strategy and business model were right for Barclays before recent events, and they remain right for Barclays now."

The bank would not be rushed in identifying successors to Mr Agius or Bob Diamond, who quit as its chief executive last week, the executives said.

Sir Mike Rake, the deputy chairman, is regarded by leading shareholders as the favoured candidate to replace Mr Agius, although he has not yet been formally invited to take the post or put his name forward for it.

Addressing the executive vacuum left by the departures of Mr Diamond and Jerry del Missier, chief operating officer, the executive committee said that Mr Kalaris would take charge of Barclays' execution and operations committee.

And they warned that the harm to Barclays could continue for a protracted period.

"We are also building an overarching brand recovery plan, which will engage all of our stakeholders, especially customers and clients, in a process to begin to rebuild the trust that has been so badly damaged," the memo said.

In addition to Mr Agius, the authors of the note to staff were Chris Lucas, finance director; Antony Jenkins, chief executive of retail and business banking; Rich Ricci, chief executive of corporate and investment banking; Maria Ramos, boss of Barclays' South African subsidiary, Absa; Tom Kalaris, chief executive of wealth and investment management and chairman of Barclays' Americas operations; Sally Bott, group human resources director; Robert Le Blanc, chief risk officer; and Mark Harding, group general counsel.

Barclays declined to comment.