Rona Fairhead, the current head of the BBC Trust and chair of HSBC’s audit committee at the time covered by the HSBC files, has declined to respond to queries about how much she knew about activities at the bank’s Swiss subsidiary.

Fairhead, who took the chair of the BBC’s governing board in 2014, has been a non-executive director of HSBC since 2004, and was made the chair of the audit and risk committee – which bore responsibility for governance and compliance across the global bank – in May 2007.

In its statement to the Guardian in the wake of the publication of bank documents, HSBC admitted “past compliance and control failures” in the group.

HSBC’s accounts detail the role Fairhead’s committee played at the bank during her chairmanship. The audit committee, the document states, “meets regularly with HSBC’s senior financial, internal audit, credit, legal and compliance management” to consider the bank’s “internal control, compliance and risk management”.

The committee met seven times in 2007, the final year covered by the documents leaked by Hervé Falciani.

As chair of the BBC Trust, Fairhead is ultimately responsible for overseeing the organisation’s editorial standards, as well as serving as an auditor to ensure the licence fee payer receives value for money.

Under questions last year from the culture, media and sport select committee in parliament, Fairhead defended her role at HSBC, but admitted failings related to the record-breaking $1.9bn fine levied on the bank by US authorities in relation to money-laundering in its Mexican branch.

“One has to be realistic and sometimes bad things do happen,” she told MPs at the hearing. “Sometimes the controls you think are effective turn out not to be so … The only way to respond if you made a mistake is to apologise – that is absolutely what we have done.

“We have been very clear that money is no object in fixing that, and to put systems in place to ensure it will not happen again.”

Fairhead stepped down from the audit committee in 2013, taking a new role as chair of the bank’s financial system vulnerabilities committee, the same bank committee that former HMRC permanent secretary for tax, Dave Hartnett, joined in 2013.

Fairhead has recently stepped down as chair of that committee, but continues to juggle a role at HSBC with her BBC duties, currently serving as chair of the bank’s North American division.

The Guardian posed a series of detailed queries to Fairhead through the BBC Trust regarding the extent to her knowledge of the activities of HSBC’s Swiss arm, as revealed in the HSBC files, including whether she was aware the bank was handing out “bricks of cash” to clients, or aggressively marketing vehicles to circumvent Swiss tax treaties.

The BBC Trust referred queries regarding Fairhead’s role at HSBC to the bank, which referred to its initial statement to the Guardian, and said her roles and responsibilities at the bank since 2004 were detailed in its published accounts.

Asked whether Fairhead thought her continued directorship at HSBC was compatible with her BBC role, or whether the compliance failures of the bank under her watch reflected on her suitability as a BBC Trust chair, the Trust said the HSBC issue was unrelated to the BBC.

“This issue has nothing to do with Rona Fairhead’s role as chairman of the BBC Trust,” a BBC Trust spokesman said.

Alongside her roles at the BBC and HSBC, Fairhead also serves as a non-executive director at PepsiCo.