Three students are believed to have been arrested after dropping a banner reading “traitors not welcome – hate clegg love ncafc” from the building in which the Liberal Democrats are holding their party conference.

The students, who are supporters of the group the National Campaign Against Fees and Cuts, have been told they will be held until the end of the conference, according to people familiar with the action. It is believed that they are being charged with traffic offenses. Two other protesters had their details taken by the police.

The action comes as students across the country return to campus for freshers’ weeks, and launch a fresh wave of protests against fee rises and cuts to university funding.