Students attending a debate about sharia law at an East End university were threatened by a man who stormed into their lecture theatre and told them he would “track them down”.

The man also filmed attendees at Queen Mary, University of London’s Mile End Road site before threatening them with violence if they said anything negative about the Prophet Muhammad.

Campaigner Anne Marie Waters had been invited to give a speech by the university’s Atheism, Secularism and Humanism Society when the drama unfolded on Monday evening.

Organisers called the police and the event was cancelled.

Ms Waters said in a blog for the National Secular Society: “Just before I was due to start, a young man entered the lecture theatre, stood at the front of the room with a camera and proceeded to film everyone in the audience.

“That done, he informed us that he knew who we were, where we lived and if he heard a single negative word about the Prophet, he would track us down.”

She added that it was a “frightening experience” and said “people felt genuinely threatened and upset”.

Police confirmed they are investigating the incident and the university said it is conducting its own probe.

Queen Mary’s principal Professor Simon Gaskell said: “Talks, meetings and debates are held peacefully at Queen Mary on a daily basis and we will continue to host such events.

“We will do our utmost to ensure this occurrence is not repeated and that our students are able to gather and engage in debate freely without interference of any kind.”

Queen Mary Students’ Union said: “Our students’ safety is of absolute priority and we take such reports very seriously. We are confident our processes have been followed in organising the event.”

There were no injuries, police said.

The Met added in a statement: “Police were called at approx 7pm following reports of a man being threatened by another man. Officers attended and the victim was located and spoken to.”