The Norton Rose M5 alliance of six law firms is to split up this August to allow each member firm to concentrate on individual expansion.
The move will clear the way for Norton Rose to pursue its target of a US capacity either by merger or acquisition, while the provincial members of the alliance will concentrate on achieving a place among the top dozen domestic law firms a rung below the big five.
The group, founded in 1977 and joined by Norton Rose in 1990, shared training and a precedent database and, when it suited them, used the M5 Group name in beauty parades for clients.
Norton Rose senior partner David Lewis said: "A national law firm is something we all thought might be a good idea some years ago. That hasn't come to fruition."
The group's association agreement allowed for a review of the arrangement every three years. After a review at the end of 1993 the board of the M5 group voted against merging into one firm because they found that clients did not want it. It also decided not to split.
But from that moment, explained Mark Jones, managing partner of Addleshaw Booth & Co, the firms began pursuing their own strategy with Leeds member Booth & Co merging with Manchester member Addleshaw Sons & Latham last year and Plymouth, Southampton and Exeter member Bond Pearce acquiring first the Southampton office of Boodle Hatfield and then the entire Southampton firm Hepherd Winstansley & Pugh.
Meanwhile, Norton Rose is looking to expand in Europe and the US.
However, the top tier of US firms do not see the need to dilute their equity with a UK firm below the big five, particularly when the domestic US market is so huge.
Lewis said that all options were being considered: from a full merger, to a loose or close association or a joint venture of the securities practice alone such as the one Simmons & Simmons has signed with New York-based Fried Frank Harris Shriver & Jacobson.
Mills & Reeve senior partner Jonathan Barclay said that he saw advantages in individual members now forming their own mini-alliances with each other. He said Mills' practice had many similarities with Bond Pearce.