Nobody can accuse Sullivan & Cromwell of rushing headlong into the UK corporate market. Indeed, the phrase 'softly, softly' could have been invented to describe the way the firm has gone about building a UK-law presence in London.

It has been circling the City market for as long as Legal Week has been in existence. The front page of our inaugural issue, in January 1999, reported on Sullivan's first foray into UK law with the hire of Norton Rose project finance partner Jamie Logie.

That was seven years ago. Next month the London office will welcome its fifth English law-qualified partner through its doors in the shape of Tim Emmerson, who is jumping ship from Milbank Tweed Hadley & McCloy.

Far more significant than the number of UK partners the firm now boasts is the fact that it is finally launching a fully-fledged corporate practice. Initial reactions from the City's tight-knit M&A community suggest the move makes sense, especially given Emmerson's links with Goldman Sachs.

But there will also be quiet satisfaction that Sullivan has not succeeded in prying a big name away from the magic circle, having spent at least two years plotting its UK corporate launch. And, of course, the move is double-edged for US firms in London generally, given the fact that Sullivan's gain is Milbank's loss – raising as it does inevitable questions about Milbank's ability to sustain its recent eye-catching efforts to ramp up its presence in Europe.

It is normal on such occasions to question the impact of such hires on Slaughter and May, given that Sullivan is supposedly one of Slaughters' 'best friends'. Well, Slaughters has certainly had plenty of time to get used to the incursions of Sullivan, Simpson Thacher & Bartlett and Davis Polk & Wardwell into UK law. It nevertheless remains an uncomfortable truth that Slaughters is powerless to prevent such forays into its home territory.

It is also worth bearing in mind that Sullivan is intent on replicating the success it has already achieved in Paris – a consideration that makes Slaughters' approach look just a tad parochial when compared with its supposedly ultra-conservative US counterparts.