Edinburgh University students have been banned from wearing "offensive" fancy dress costumes, such as those portraying Arabs, Nazis and Pocahontas.

The new costume policy from Edinburgh University Students Association (EUSA) follows a row over "black face" costumes on campus.

It implemented the new policy ahead of Halloween, urging students to "show respect and consideration for each other by avoiding costumes which might cause offence."

The policy has proved controversial and a petition set up to "reinstate" free speech at the university has attracted hundreds of signatures.

"Black face" costumes and those based on "based on racial or cultural stereotypes" are banned, including costumes portraying Arabs, Nazis, police brutality, slavery, Mexicans, Native Americans, gangsters and Pocahontas, according to the policy.

Mental patient costumes are also banned as they "mock or are based on stereotypes of disabled people".

Costumes of "camp" men, Caitlyn Jenner or "cross-dressing for the point of humour" are also forbidden.

Fancy dress portraying Chris Brown, Jimmy Savile and Ched Evans is also banned as it uses "gender-based or sexual violence for the purpose of humour."

The final part of the policy advises students: "If you still unsure as to whether or not your costume might be considered inappropriate or offensive then it probably is so don’t wear it."

In 2013, a group of students from the University's Law Society "blacked up" to portray Somali pirates, which led to them being carpeted by chiefs in the institution's law school.

Philosophy student Charlie Peters set up a petition calling for free speech to be "reinstated" at the university.

It was recently ranked among the most “ban happy” universities in Spiked magazine’s Free Speech University Rankings 2016.

EUSA declined to be interviewed by STV News but the student union has defended the ban, saying it wants to ensure everyone is able to have a great night out at its venues.

An article by the union's leading officers said: "Our position on fancy dress costumes has been developed in response to student feedback.

"We think it’s important to ensure that none of our members are prevented from enjoying a great night in our venues so we want people to consider the impact their costume might have on others.

"We think it’s important to highlight that our policies are there to broaden free speech, not to restrict it.

"We’re committed to ensuring everyone feels able to participate in debate and discussion within our venues"