When Reed Smith merged with Warner Cranston back in 2000, it pledged a long-term commitment to Europe. Now it has come back for more, and in spades. Richards Butler is the largest London firm yet to (in principle) agree a takeover by a larger US firm. The scale of the Pittsburgh firm’s ambition is reflected by the fact that its London office will become its largest if the deal goes through, accounting for more than 20% of its turnover.

Many will be tempted to regard Reed Smith as an upstart from America’s rust belt, especially given the fact that its average profits per partner are lower than Richards Butler’s – $800,000 (£425,000), compared with £460,000.