Students at a Scottish university have been banned from dressing up as Mexicans, gangsters, mentally ill people and even rapper Chris Brown following a series of 'blackface' scandals.

The crackdown has been imposed by student union leaders at Edinburgh University, and also bans costumes of 'camp men', Native Americans, Pocahontas and transgender former Olympian Caitlyn Jenner.

But some students are furious at the rules, branding them 'ridiculous' and a 'joke' and have now launched an online petition demanding the university 'reinstate Free Speech.'

It has gained more than 800 signatures so far.

The crackdown has been imposed by student union leaders at Edinburgh University after students dressed up in 'blackface' in 2013. They have now banned costumes of 'camp men', Native Americans and Pocahontas

EUSA President, Jonny Ross Tatam, said their policies are intended 'to broaden free speech, not restrict it. We're committed to ensuring everyone feels able to participate in debate and discussion within our venues'

The Edinburgh University Students' Association (EUSA) introduced the rules following a series of scandals involving students 'blacking up'.

In the new costumes policy students have been told: 'You may not intend to hurt anyone when picking out your costume, and you may not even think there's a problem, but it's important to consider the impact your choices will have.'

The costume policy adds: 'It is also not acceptable to use props to emphasise racial characteristics in order to convey an individual or character.

'A good costume should be clear enough that you do not need racial or cultural additions.'

The guidance has prompted a backlash from many students as well as from Spiked, an online 'humanist' magazine, which posted an image of a child dressed as a gangster writing, 'Who's afraid of this little guy?'.

A student has launched an online petition (pictured) demanding the university 'reinstate Free Speech'

Charlie Peters, 19, a philosophy student at Edinburgh University has started an online petition asking the institute to reinstate free speech.

He said: 'It's a bit of a joke. We have a national approach of strict laws in censorship of speech. The uni has taken that and gone beyond and to absolute extremes.

'I'm sure their intentions are nice, but it takes away the potential to speak freely.'

In the open letter he posted online, he wrote: 'In a free and liberal society such as ours, it is imperative that people remain able to express their views, regardless of what others may think of them.

'This is currently not possible at the University of Edinburgh. By upholding the values of the NUS’s ‘No Platform’ policy – and as a result of your ‘Safe Space’ policy – you have restricted the right of students and guests to speak freely.

'By defining university as a ‘Safe Space’, you shelter students from dissenting views, betraying the most basic ideals of education.'

Edinburgh was recently ranked as one of the most 'ban happy' universities in Spiked magazine's, Free Speech University Rankings 2016.

In 2013 the Edinburgh University Law Society were forced to justify their actions after four students 'blacked up' to represent Somali pirates during a drinking event

Tom Slater, the coordinator of the rankings, said: 'The university that produced David Hume is banning fancy dress.

'Edinburgh was among the worst universities we assessed nationwide. The Edinburgh Union Students' Association, in particular, has outdone itself.'

He added: 'Our research shows that in Scotland - as it is across the country - campus censorship is hitting epidemic proportions.'

Previous bans made by EUSA have included social media site UniLad, Page 3 and Robin Thicke's hit Blurred Lines from being played on campus.

In 2013 the Edinburgh University Law Society were forced to justify their actions after four students 'blacked up' to represent Somali pirates during a drinking event.

EUSA President, Jonny Ross Tatam, said their policies are intended 'to broaden free speech, not restrict it. We're committed to ensuring everyone feels able to participate in debate and discussion within our venues.'

Dundee University has also faced criticism after banning Pro-life groups in 2014 - despite them having their own stall on campus for years before.

And Stirling University introduced a policy to not 'share a platform with any organisation deemed to be racist or fascist by the National Union of Students.'