I applied through a staffing agency. The process took 1+ week. I interviewed at ADVFN (London, England) in Mar 2015
Interview
Interview is with a phone call, or if you're in the same city they might call you in. First of all they send an e-mail to confirm the place and time of the Interview and it's done via Skype.
Interview questions [1]
Question 1
They want to know more about your past experience and your interest in the financial sector, or whatever your internship is about (ex. programing). If it all goes well and they see you're motivated they will accept your internship.