John McIvor, the bank's head of international communications, told CNBC.com that he could not confirm the circumstances surrounding Erhardt's death, though he did provide some insight into the life of an intern.

"The whole point about internships is to give students a positive experience and to get to know our firm and us to know them well, so we can work out who would be the best fit to join the company full-time after they graduate," he said.

"I'm not going to comment on what hours people choose to spend in the office voluntarily," he added. "But if you think about it logically, what we're trying to do is something that happens across all the big firms. We're looking to get to know them better."

The Independent reported that it spoke to others familiar with the matter who confirmed how grueling life can be for interns:

One former investment banker confirmed that interns could regularly work 14 hour days.

The banker, who wished to remain anonymous, told The Independent: "Interns can regularly clock up to 100 or even 110 hours a week, but people are fully aware that banking is hard work and the company constantly reminds you to manage upwards in order to not overheat. This is the first time I've heard of something like this happening and banking is a very close culture."

—By CNBC's Jeff Cox. Follow him @JeffCoxCNBCcom on Twitter.

