Protesters against an upcoming speaking event with an academic who accused the late Cambridge professor Jason Arday of plagiarism have placed a Ku Klux Klan hood on a controversial statue of the 19th Century colonialist Cecil Rhodes.

Nathan Cofnas, a self-defined “race realist” who argues genes play a “non-trivial role” in intelligence differences between racial groups, is due to speak at an event at Oriel College in Oxford later this month.

Objecting to the event, the campaign group Led By Donkeys placed a white Ku Klux Klan hood and a sign reading “Racists Welcome Here” on the Rhodes statue at Oriel College on Thursday morning.

In response to the protest, the college said it was “committed to upholding freedom of speech within the law and has a statutory duty to do so”.