Jeff Triggs, a partner of City solicitors Slaughter and May, has been invited by Pilkington's management to advise on the deal.
"If it's an agreed merger, you might get a City firm to do it for £1m," says one senior lawyer. "Most firms would bite your hand off if the work were offered for £2m. Slaughters might well ask for £4m."
This, despite Herbert Smith's being the lawyers that have done the bulk of Pilkington's work since the 1980s. Pilkington's management, chaired by the robust Derby County supporter Sir Nigel Rudd, who built major conglomerates such as Kidde through the 1980s and is also chairman of in-play Boots, necessarily feels that shareholders are going to get value for money by switching to Triggs and Slaughters.
"He's got a great negotiating style," says one participant in a professional de-merger on which Triggs worked. "He set a really positive tone and got things done in double-quick time, while serving the interests of both clients."
"A switch of lawyer often happens in the end game," says one observer. "It's often a function of whom the executives feel most comfortable with to do the final, really important deal."
Some are surprised that Slaughters, which charges premium rates because of what is perceived as its unparalleled relationships with the boardrooms of UK plc, didn't use a more senior figure, such as the older and better-known Nigel Boardman.
Despite not having a classic, blue-blooded background (he attended Gorleston Grammar School and University College, London), the clubbable Triggss, who apparently plays the trombone well and golf rather badly, is in the driving seat. "He's absolutely charming, ultra-efficient - and, for a City lawyer, really quite lucid," says one client.
In his mid-40s, with short, brown hair, Triggs has worked on a series of deals since qualifying at Slaughters in 1985. Made a partner in 1993, his more notable transactions include a deal for the Royal Mail, which borrowed £1bn from the Government in 2002. More recently, he led a joint venture deal between the Post Office and the Bank of Ireland for the marketing of financial services. He was also prominent in Resolution Life's £850m acquisition of Royal & Sun Alliance's life insurance business.
"If [Pilkington] succeeds in raising the price, Triggs is the man to get the deal done," says one banker.