If London legal recruiters are to be believed,  just about every partner at a top U.K. law firm is sitting by their phone, waiting for the call: "[U.S. firm] has expressed an interest in you…"

Then, once it happens, the exhilaration reaches such a pitch that all those lovely things that the best U.K. firms have become famous for—like locksteps, collaboration, armies of knowledge lawyers and PSLs, beautifully curated libraries, robust and regimented training schemes etc—are soon forgotten about.