The Solicitors Regulation Authority (SRA) has confirmed that it has opened an investigation into Allen & Overy's (A&O's) role on a historic sexual harassment settlement with disgraced movie producer Harvey Weinstein.

SRA chief executive Paul Philip appeared before the Women and Equalities Committee investigating the abuse of non-disclosure agreements (NDA) today (25 April), to face questions over the regulator's position on the use of such agreements by law firms.

He was specifically asked about the whether the SRA has taken any action over the revelation last year that A&O was involved in drafting an NDA for Weinstein in 1998, after the producer's then-assistant Zelda Perkins accused him of sexual harassment.

Philip confirmed that the regulator has asked for "the relevant documentation" from the firm, and that it will take action if it finds any A&O lawyers have breached SRA guidance.

A&O partner Mark Mansell appeared before the Women and Equalities committee last month to face questions over his work on the NDA, and committee chair Maria Miller MP stated that following that evidence session, the committee wrote to A&O to advise it to self-refer itself to the SRA over its role on the case.

She said Mansell had replied to the committee to inform it that A&O's compliance officer had met with the SRA, and that the SRA had communicated it would not be taking action against the firm.

However, Philip confirmed today that the SRA had opened an investigation into the firm. He said the SRA had first contacted A&O's compliance officer on 28 November last year, but had waited "for further information to come to light" before it decided whether to open a case. He added that the SRA had not asked the firm for a copy of the NDA at that time.

Conservative MP Philip Davies questioned the SRA's approach, saying: "It leaves a taste in the mouth that the SRA's relationship with firms is like a cosy old boys' network… involving scratching backs and not taking things seriously."

At last month's hearing, Mansell was asked by committee chair Maria Miller MP whether he regretted the way in which the NDA had been drawn up. Mansell conceded that, in hindsight, he would have "made it clearer that the ability to participate in a criminal process was not in any way restricted".

The committee's inquiry came after the SRA recently warned law firms in England and Wales not to use NDAs to prevent the reporting of professional misconduct within their own businesses, in the wake of several sexual harassment scandals that have rocked the profession.

The SRA and A&O declined to comment.