By Gwyn Wright.

AN Oxford University college has launched an investigation after a porter allegedly asked a black graduate if he used to ‘rob’ the place.

The former student claims a porter at St John’s College asked him if he used to ‘clean the windows’ or ‘rob’ the college during a nostalgic visit to his former halls of residence on Tuesday.

Jaqen H'ghar, using Twitter handle Mr Wahala, tweeted: “I went to my old college in Oxford yesterday to look round again. At the door I explained to the porter that I used to go there, and he replied ‘What did you do, clean the windows? Rob it?’’

An investigation was launched after he complained to the college.

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In a statement, St John’s said: “St John’s College is committed to ensuring the welfare and wellbeing of a diverse college community, and there is no place for discrimination of any kind.

“We are aware of a Twitter post about discriminatory language used by a member of staff towards a visitor and are investigating this incident as a matter of urgency and will take action if appropriate.”

The post has been liked around 1,000 times.

Mia Farraday tweeted: "This is legitimately awful. Sorry you went through that. It's disgusting."

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Rosie, using the Twitter handle @JustALittleRoo, tweeted: ''I am so sorry you went though this! Congrats on getting through Oxford by the way, you're clearly an amazingly talented person and deserve so much better than this.'' 

Last year, the Oxford Students Union said porters should go on unconscious bias training after complaints about the disproportionate number of black students being questioned about why they had entered college grounds.