The Browne report is soon to be published, which is expected to recommend raising the cap on tuition fees for university to either 7k or 10k per year. In order for this to become law, the Tories need the Lib Dems to vote either for it, or abstain. The terms of the coalition prohibit them from voting against a rise in university fees.
However. Before the election EVERY Lib Dem MP (including Nick Clegg, Vince Cable et al) signed a very public pledge that said "I pledge to vote against any rise in student fees". So how does that work?