Withers is facing a House of Commons investigation after an MP accused the firm of undermining parliamentary privilege.
The firm is alleged to have committed a contempt of parliament after sending an email to Liberal Democrat MP John Hemming in an attempt to stop him repeating allegations about an unnamed client.
The email asked that Hemming, the member for Birmingham, Yardley, undertake “not to repeat the allegations or any similar allegations, particularly in parliament”.
Speaker John Bercow yesterday chose to publish the email in Hansard, the parliamentary record. Today, a motion from Bercow to launch an investigation was unanimously carried by the Commons.
Hemming said: “I think they [Withers] showed a lack of knowledge of constitutional law and lack of respect for parliament. It’s someone trying to gag MPs on what they can say in parliament - it goes to the heart of what parliament is about. If you try to gag democratically elected people then you have a real problem.”
A Withers spokesman said: “In defending our client’s reputation, at no stage did we attempt to limit Mr Hemming’s parliamentary privilege, as correspondence to the speaker makes quite explicit.
“Our email simply outlined that if Mr Hemming was not prepared to give an undertaking that he would not repeat defamatory allegations, then our client would not be able to settle his dispute.
“We believe that we’ve acted entirely properly and professionally in asserting our client’s rights and are confident that this’ll be proved to the committee.”
The standards and privileges committee will meet on Tuesday to decide on its course of action.
The case is similar to last year’s attempt by Carter-Ruck to stop the reporting of a parliamentary question relating to its client Trafigura (26 October 2009).
The investigation by the standards and privileges committee will be the first time it has launched a probe into the activity of a law firm for nearly 30 years.