I'm not convinced that Lib Dems should be ashamed at breaking their pledge - their manifesto was costed and developed on the basis of sole power. Let's not forgot, they are the minority party by a long way in this coalition - they had an absolutely horrendus general election.

When you come into coalition, you prioritise what's most important to you - and for the Lib dems that was the £10,000 tax rate. But something so expensive has to be paid for somehow.

The only other alternative would've been a minority Tory government, which probably would've meant another general election in six months.