Student protesters used improvised shields to try and block the arrival of Britain’s top police officer on-campus.

Metropolitan Police Commissioner Sir Bernard Hogan-Howe visit to the University of Sussex was met with dozens of campaigners.

Chanting protestors managed to get inside the Jubilee building in Falmer - but were barred from getting up the stairs to the lecture theatre by security.

Extra police were called in to escort Sir Bernard off-campus by a side entrance as opponents banged on the vans.

Students said they were challenging the commissioner over the police’s “harassment” of the public.

Alex Harris, 22, who was joined on the protest by his bichon frisé dog Lulu, said: “I think we were pretty successful in confronting the police, who routinely harass members of the public, primarily to keep the working class in check.

“The police need to be challenged.” Mr Harris also claimed some of the protesters had been punched by security staff.

Meanwhile a security guard claimed he was knocked over and assaulted by a protester.

Steve Brazier, 35, Brighton: “I was knocked over and kicked in the head. I was pulled away from the security door I was guarding.”

The University of Sussex said it had been made aware of protest and was “committed to facilitating peaceful protest on campus.”

Sir Bernard Hogan-Howe was speaking as part of the university’s LEAD speaker series, which brings in leading academic researchers and industry professionals to share their knowledge and insight of topics related to “leadership, ethics, and diversity”.

A university spokesman said: “The purpose of such events is to further the University’s aims in high quality teaching and research, through promotion of open and robust academic debate within the campus community.”

But the university’s own students union said many of its officers supported the protest.

A spokesman said: “Many of the Students’ Union officers will be attending the demonstration to show support for those still demanding justice, and call for an end to police racism and violence.”

Sussex Police said university security had requested a uniformed police presence to ensure the safe departure of Commissioner.

A spokesman said: “The departure took place without incident.

“There are no reports of injuries, and there have been no arrests.

“All other security arrangements were made by the university's security staff, and there was no other police involvement.”