A King’s College London academic who specialises in mental health has been filmed at a Brexit Party rally on Tuesday apparently calling a Remain activist a “fucking traitor”.

In the clip posted on Twitter, Dr Niall McCrae can be seen shouting and poking a Union Jack flag in the face of Femi Oluwole.

The 29-year-old Remain campaigner had set up a desk outside the event with a sign that read: “A no-deal Brexit would be a disaster for the UK. Change my mind.”

As McCrae repeatedly shouts “fucking traitor”, another man throws water from a bottle over Oluwole. McCrae is later seen in the video shaking hands with the man. 

McCrae is a senior lecturer at King’s College London and has written a book titled The Story of Nursing in British Mental Hospitals.

He appears to have deleted his Twitter account since the incident and also a blog post written just before the rally in which he says: “Footage of the Olympia rally will enter the history books.

“And the tactics of Remain opponents will be recorded as a categorical error. Their smearing of Leavers as thick racist bigots is no longer working, and has become counterproductive.”

Oluwole told HuffPost UK: “I was pretty disgusted to discover that the man who chose to hurl generic populist abuse at me and poke me in the face with a flagpole, rather than debate an issue which could ruin the futures of younger generations, is actually responsible for educating younger generations.”

McCrae previously caused controversy in 2016 when he called LGBT activists at his university the “Gaystapo” and “sanctimonious petty Napoleons”.

A King’s College London spokesperson said: “We are aware of complaints regarding the conduct of a member of our staff. We do not condone inappropriate or abusive behaviour. This is being taken very seriously and is being dealt with as a priority.”

McCrae has been contacted for comment.