The process involved emailing the HR department, and then going in for an interview with two of the partners who asked questions for about 30 minutes. Very formal questioning style, and very serious. They took a very long time to get back to me, and it took some pushing to get a response.
I applied through an employee referral. The process took 2 months. I interviewed at A&O Shearman (London, England) in Oct 2012
Interview
Standard big-law interview process -- fly out to London, meet with six or seven partners and associates serially in a conference room, followed by a dinner with a couple of associates to answer questions.