The problem they face is that the Coalition is set to increase tuition fees - with Lib Dem Business Secretary Vince Cable overseeing the policy - and the party leadership has promised they will only abstain rather than vote against the changes.

Birmingham MP John Hemming (Lib Dem Yardley) says on his blog that "I have not yet made up my mind as to which way to vote".

It seems to me that this is a major change from "I pledge to vote against any increase in fees in the next parliament and to pressure the government to introduce a fairer alternative", which is what Mr Hemming signed before the election.

Having said that, Mr Hemming seems to be arguing that the reformed system to be introduced by the Government is indeed a "fairer alternative", and therefore the first part of the pledge is no longer applicable.

Solihull's Lib Dem MP Lorely Burt takes a different approach. Like Dr Cable, she says the financial situation is so difficult that they have to do things they don't like.

I don't want to pick on the Lib Dems too much. Parties in a coalition government - whoever's involved - need to strike deals and make compromises. This would be just as true for the Lib Dems if they'd done a deal with Labour (and true for Labour too).

But the idea that the Coalition suddenly discovered how bad the budget deficit is once they came into power can't be allowed to take root.

They knew things were tough during the election campaign. The deficit is not new.