Freshfields Bruckhaus Deringer has been brought in by UBS to review the Swiss banking giant's handling of a female trainee's allegation that she was raped by a male colleague.

The complaint first came to light earlier this summer, and UBS has now kicked off a review of how it handles such cases.

In a statement, the bank said it had deployed an "internal expert team" to conduct a review, which it said it "regularly" does after significant cases.

UBS said that Freshfields had been brought in to "provide an independent assessment from an outside party and draw from broader industry insights".

Both the woman in question and the alleged perpetrator are understood to have left the bank.

Freshfields has a longstanding relationship with UBS. Recent major mandates have including advising the bank on the 2016 combination of most of its European wealth management business into UBS Europe.

Notably, Freshfields' New York white-collar crime partner Aaron Marcu helped to secure a high-profile win in the 2014 trial of Raoul Weil, the former CEO of UBS's wealth management division.

Weil, who had been charged by the US Department of Justice of allegedly assisting US taxpayers in evading taxes on assets held in Switzerland, was cleared after a lengthy case in which he was represented by Marcu and US law firm Kobre & Kim.

Freshfields declined to comment.