Tim Jones and Barry O’Brien have already faced a tribunal over the allegations that there was a conflict of interest when Freshfields Bruckhaus Deringer was instructed by Philip Green on his 2004 bid for Marks & Spencer (M&S). Now they have to face that trauma all over again.

Both Mr Justice Lawrence Collins and the High Court found against the firm back then, kicking Freshfields off the £9bn deal. Now Jones, the firm’s London head of corporate, and O’Brien, formerly global corporate chief, await a Solicitors’ Disciplinary Tribunal hearing over the same allegations.

Careers have gone on hold while the Law Society’s two-year probe into the alleged conflict has been trundling on. O’Brien was effectively barred from Freshfields’ senior partner election. Free from the burdens of leadership, O’Brien has made full use of advantageous pensions rights and retired from the partnership. He is now a consultant at the firm, but without the Law Society probe hanging over him he would have been freer to pursue a second career elsewhere.

But now that the Law Society Regulation Board has formally applied to the tribunal for it to hear the case, the Freshfields defence team has swung into motion. Handling of the case has moved from the firm’s litigation head Ian Terry to Ashurst partner Ed Sparrow and Herbert Smith partner David Mayhew for O’Brien and Jones respectively.

Sparrow and Mayhew do not appear on the roster of solicitors who routinely defend cases before the Solicitors’ Disciplinary Tribunal, but both are hugely experienced litigators.

Mayhew joined Herbert Smith just 10 months ago from the Financial Services Authority (FSA), where he was acting director of enforcement and ‘leading advocate’. During his time at the FSA, Mayhew represented the authority in many Financial Services and Markets Tribunal cases. He has also acted for financial institutions and senior management in investigations before the Serious Fraud Office and other such organisations.

Meanwhile, Sparrow’s experience is broadly similar, having recently represented Shell executive Walter van der Vijver on the FSA’s probe into Shell’s reserves. Like Mayhew, Sparrow has also worked on the other side of the fence, advising the FSA on fending off Yukos’s attempt to delay the IPO of Russian state oil giant Rosneft earlier this year.

Sparrow’s and Mayhew’s lack of Solicitors’ Disciplinary Tribunal experience would be alarming were it not for the fact that this case is uncharted territory for everybody. Although the tribunal routinely hears conflict cases connected with conveyancing or probate matters, M&S-style issues are unheard of.

As one solicitor involved with prosecuting tribunal matters put it: “I think it’s fair to say that this style of intergalactic conflict that this case involves has not appeared before the tribunal.”

Although as advocates Mayhew and Sparrow could argue Jones’s and O’Brien’s cases themselves, a canny move would be to bring in the only two leading counsel who regularly appear before the tribunal: Fountain Court’s Tim Dutton QC and Gregory Treverton-Jones QC of 39 Essex Street. Their knowledge of the system, as well as their commercial law savvy, could prove a boost to the Freshfields Two’s case. Dutton’s chambers head Michael Brindle QC fought for Freshfields over M&S in the High Court.

The Law Society, on the other hand, has instructed Geoffrey Williams QC to argue its case. Williams is one of the most experienced prosecutors on the Law Society’s panel and is the solicitor-advocate to whom the society most often turns when a case is appealed to the High Court.

In 2006 alone Williams has handled five High Court appeals for the society, including former Olswang consultant Julian Holy’s appeal against the tribunal’s decision to strike him off the roll. Williams generally handles the advocacy himself, sometimes with the support of junior counsel, and is usually instructed directly by the Law Society – helping to keep costs down for the organisation.

The battle promises to be a fascinating fight between a raft of lawyers with decades of experience between them, as Freshfields conflicts system is laid bare to the world.