The dispute between Field Fisher Waterhouse and Dr Mark Abell, its head of IP and Tech, has turned into a full on playground spat after it emerged that Abell has instructed Herbert Smith Freehills to represent him against FFW.

Abell was suspended by FFW at the end of January after he announced that he had "outgrown" the firm and was off to Bird & Bird. He said that he'd "been in negotiations with the firm for an orderly and good-natured exit" and was mystified as to why it was being so hard on him. Hmmmm, possibly that's because, according to RollOnFriday sources, he'd presented the firm with a lengthy letter from Herbert Smith explaining how he could drive a coach and horses through its partnership agreement and was entitled to go wherever he wanted whenever he wanted.

FFW took its own advice from Winckworth Sherwood, told Herbies to sling its hook, and sent Abell off to sit at home with his thumb up his fundament.

That's another cunning plan, Baldrick

And there he still is, as both sides continue merrily to brief against each other. The Lawyer reported that Abell controlled around £15m of revenue, while insiders at FFW mutter that the true figure is about 10% of that. Ultimately neither side emerges with much credit, and Bird & Bird must be wincing at all the bad publicity surrounding its new hire. So much so, in fact, that it has declined to confirm his appointment.

Neither Bird & Bird nor FFW would comment.