Nick Clegg issued an apology in 2012 for backtracking over tuition fees / Getty

Free University of Sheffield organisers were protesting over the cost of higher education in the UK

Students occupied Nick Clegg's Sheffield Hallam constituency office today, in protest against the cost of higher education.

Images posted on Twitter show the protesters holding up banners outside the Deputy Prime Minister's office alongside the hashtag #OccupyClegg.

They briefly entered the building itself but left after police arrived.

The demonstration, organised by the Free University of Sheffield, was a response to the Liberal Democrat leader's broken pledge at the last General Election to oppose any increase in tuition fees. Students can now be charged up to £9,000 a year.

Chris Saltmarsh, a Free University of Sheffield organiser, told The Independent  that the protest sought to turn Clegg's office, which has become "symbolic of betrayal and hypocrisy" into a "non-hierarchical space".

"We believe they [the Liberal Democrats] betrayed a generation of students," he said.

Saltmarsh, who is a student at the University of Sheffield, also said the organisers planned to hold seminars throughout the day addressing the "failings of liberal democracy".

In 2012 Clegg issued an apology for backtracking over tuition fees. In a party politcal broadcast that was aired nationally he said: "There's no easy way to say this: we made a pledge, we didn't stick to it - and for that I am sorry."

A Liberal Democrat spokesperson told The Independent: "Earlier today, a small group of people briefly entered the office. They were asked to leave by a member of staff but refused.

"The police were called and the group left peacefully after a short sit in protest."