Bank Restaurant Group, the company that employs the wife of Pinsent Curtis Biddle's senior partner as a director, is suing her husband's firm for negligence.
Julian Tonks, senior partner of Pinsents, is married to Bank Restaurant Group marketing director and board member Ann Tonks.
The claim is aimed at partners of the old Biddle firm, which merged with Pinsent Curtis in 2001. Julian Tonks is legacy Pinsents and so is not in the frame for negligence.
The Lawyer understands that the company has constructed an internal Chinese wall to prevent any disclosure to Ann Tonks of the ongoing litigation.
The claim centres on the 2000 deconstruction of the old BGR chain of upmarket eateries, which split into two: Bank Restaurant Group and another group that included the Fish! chain, which is now in administration.
Biddle advised the Bank Restaurant Group on the buyout of the restaurants in that group, including the Bank restaurants in Aldwych and Westminster, and an AIM placing to fund the deal.
Bank Restaurant Group brought the claim because, in the simplest terms, the price of the group was stated differently in the sale contract and the AIM prospectus.
Only Biddle partners will defend the claim, which including interest and costs is likely to exceed £1m.
A Pinsents spokesperson said: "This is a historic claim that dates back to before the merger between Pinsent Curtis and Biddle. It's been brought by the Bank Restaurant Group and relates to [work] carried out at Biddle. The claim is being contested vigorously."
Bray Walker is acting for the claimant, with Barlow Lyde & Gilbert representing Pinsents.