"If I was David I would have said I'd had a f***ing terrible year." With William Charnley last week taking the total number of partners to quit McDermott Will & Emery's City arm to 11 in little more than a year, there are no prizes for guessing which US firm's London managing partner a rival was describing above.

Less than a decade after one of the most high-profile London debuts by a foreign firm, from the outside it all seems to have gone more than a little bit wrong for McDermott.

Of the six high-profile names that helped launch the office, only tax partner – and new senior partner – Peter Nias and managing partner David Delgarno remain. Aside from Charnley, the office has also lost its employment head, Fraser Younson, and its former managing partner and litigation partner John Reynolds, while its banking head, Graham Rowbotham, retired at the end of last year. And, as other recent departures to firms including White & Case and Clyde & Co testify, it is not just long-serving department heads that have had enough.