The Association of Christian Financial Advisers has come out in support of calls for a mandatory code of conduct for the banking industry.

The ACFA said it wants to see ethics put back at the centre of banking and a return to the founding Quaker principles of "honesty, integrity and plain dealing".

Barclays chief executive Bob Diamond announced on Tuesday that he would resign following news of the Libor rate-rigging scandal. He is due to appear before the parliamentary Select Committee on Wednesday.

Barclays chairman Marcus Agius, who announced his resignation, one day before, will now become full-time chairman and oversee the process to appoint Mr Diamond's successor.

Arwyn Bailey, of the ACFA, welcomed the accountability shown in Mr Diamond's resignation.

"In falling on his sword and resigning Bob Diamond has done the honourable and probably inevitable thing. The pressure must have been intolerable, for both him and his family," he said.

"Without question Mr Diamond is the man who carries the can, but given such pressure for him to resign, who would be willing to step into his shoes?

"The level of expectation and condemnation may cause others to question their willingness to take up the mantle of leadership. It may even result in the recruitment of leaders of lesser ability."

ACFA spokesman Adian Vaughan added that there was a need for a successful and well-run investment and high-street banking service that could facilitate growth and compete on a worldwide scale.

"LIBOR is a side-issue as the overall effects would have largely been neutral - marginal winners and losers," he said.

"The big issues are collusion, an acceptance of 'doubtful practices' and a 'sales culture' that relegates trust below that of short-term profit / bonus maximisation.

"Business culture starts from the top and cascades downwards. Recovering a positive culture would be far better than excessive regulation that could drive wealth-generating banks overseas. Back to basics if you please."