LONDON — During his tenure as Barclays chief executive, Robert E. Diamond Jr. spoke passionately about creating a strong culture of integrity and trust, a common philosophy that would breed success at the big British Bank. In a speech last year, he emphasized that the ‘‘evidence of culture is how people behave when no one is watching.’’

But now Diamond, who stepped down last week, faces criticism about his leadership as Barclays deals with fallout from a scandal involving interest rate manipulation.

On Tuesday, Barclays released new documents that indicate British regulators had raised questions about Diamond’s management style, with concerns dating to his appointment to the top spot in late 2010. The scrutiny of Diamond came months — and in one case, years — before the bank came under fire for trying to manipulate key interest rates.

The revelations, during a tense parliamentary committee hearing, could put added pressure on the bank and Diamond.

Continue reading below

“The culture at Barclays came from the top,’’ said Andrew Tyrie, a member of Parliament who heads the committee. ‘‘It came from top executives.’’

In late June, Barclays agreed to pay $450 million to settle accusations by US and British authorities that it reported false rates in an effort to improve profits and make its financial position look stronger. The case, the first major action stemming from a global investigation into big banks, focuses on a key benchmark known as the London interbank offered rate, or Libor.

To help quell the anger over the case, Diamond agreed Tuesday to forgo up to $31 million in stock bonuses that he was set to receive. Last week, the bank’s chairman, Marcus Agius, said he also would resign, along with one of Diamond’s top deputies, Jerry del Missier.

On Tuesday, British politicians directed their ire at Agius, who testified at the hearing for more than two hours. Lawmakers focused mainly on the actions of Diamond, wondering what went wrong inside the bank.

In April, Adair Turner, chairman of the Financial Services Authority, wrote a letter to Agius, addressing what the regulator perceived as overly aggressive practices at the bank. He pointed to Barclays’ efforts to avoid paying around $774 million in corporate taxes and some of the bank’s accounting methods.

“Barclays often seems to be seeking to gain advantage through the use of complex structures, or through regulatory approaches which are at the aggressive end of interpretation of the relevant rules and regulations,’’ Turner wrote.

In his testimony Tuesday, Agius said that Turner’s letter showed the bank’s ‘‘strained’’ relationship with the Financial Services Authority.

The correspondence between Barclays and British regulators appears to contradict Diamond’s evidence.

Diamond might be recalled to give further evidence next week.