Barclays analyst to interns: 'Welcome to the Jungle'

A Barclays investment banker welcomed his unit's new class of summer interns with a scary sounding list of workplace rules, ominously titled "Welcome to the Jungle."

The email from analyst Justin Kwan was intended as a joke, according to a person inside Barclays, but the hyperbolic memo has attracted attention around the Wall Street because it plays into the common perception of a brutal work culture at banks.

The email obtained by CNBC runs through Kwan's "10 Power Commandments" for the bank's Global Power and Utilities interns.

Kwan writes the interns are expected to leave the office last every night and never take off their jackets at work. Kwan recommends bringing a pillow, as it eases the "very likely scenario" of sleeping under a desk.

Keeping an extra tie or scarf could come in handy, as associates may run out of napkins, Kwan said.

Read More These interns will make more $ than you this summer

540812835
Sigrid Olsson | Getty Images

Kwan added that an intern working during his time in the group requested a weekend off for a family gathering, only to be asked to hand in his phone and pack up his desk.

In a statement, Barclays said it did not authorize the email. The firm added that it was "committed to creating an environment where both our bankers and our business can thrive."

"We have implemented policies and training guidelines to enable employees to gain valuable experience while at the same time maintaining a healthy work-life balance," Barclays added.

Read More10 tips for your summer internship

The bank declined to say whether Kwan was still employed.

Kwan did not immediately respond to CNBC's request for comment.