In recent days we’ve had a look at the Conservatives’ record in government, and how Labour got some key forecasts about the ecomomy spectacularly wrong.

Of course it’s only right that we scrutinise the Liberal Democrats too.

In some ways, it’s more difficult to be fair to Nick Clegg’s party. Because they are the junior partners in a coalition, it was always going to be difficult to meet all their 2010 manifesto commitments.

On the other hand, some of the stuff they got into the coalition agreement has never seen the light of day.

Just before the last election Mr Clegg – who once worked as a fact-checker before getting into politics – told the nation it was time to “say goodbye to broken promises“.

What have the Lib Dems failed to deliver?

Tuition fees

Probably still Nick Clegg’s most embarrassing moment as deputy PM.

He signed a pre-election pledge to vote against any increase in tuition fees for students. And he said it would be a “disaster” if fees rose to £7,000.

In December 2010 he voted to allow universities to charge up to £9,000.

Lest we forget, Mr Clegg wasn’t the only one to go back on his word. All 57 Liberal Democrat subsequently elected signed the pledge, organised by the National Union of Students, but only 21 voted against the motion in the end.

The bigger picture: the fees pledge wasn’t a key manifesto pledge for the Lib Dems and Mr Clegg famously apologised in a YouTube video.

Police numbers

Their 2010 manifesto said: “Liberal Democrats will put thousands more police on the beat.”

The coalition has cut police numbers to their lowest level since September 2001.

The bigger picture: again, not a really key pledge, and not something that made it into the coalition agreement.

Pupil Premium

This commitment to pump an extra £2.5bn into schools to help the poorest pupils, on the other hand, was a die-in-a-ditch promise for Mr Clegg’s party.

For our money, the jury is still out on the Pupil Premium. FactCheck has long questioned whether the money was really “additional”, as the Lib Dems have always claimed.

The “extra” £2.5bn followed pupils eligible for free school meals, a principle that makes school funding “even more targeted at deprived schools” and “more redistributive”, according to the Institute for Fiscal Studies (IFS).

But there has always been the suspicion that the government was merely giving with one hand and taking away with the other.

At the same time the Pupil Premium was announced, there was a real-terms cut in the schools budget. Would the one cancel out the other?

In 2011, the IFS’s answer was “not quite”. Schools spending overall would still fall slightly in real terms even with the premium, the think-tank predicted.

The obvious fear was that schools would simply use the money to plug funding gaps elsewhere, rather than channel it into improving attainment among disadvangated pupils.

Now inflation has turned out to be significantly lower than it was forecast to be.

The latest IFS calculations suggest overall spending per pupil, including the Pupil Premium, will have risen by a hair’s breadth – 1 per cent in real terms between 2010/11 and 2014/15.

So changes in inflation may just about have saved the government from accusations that it has cut spending on schools over this parliament. But all this still puts the Lib Dem claim of having negotiated an “additional” £2.5bn for schoolchildren in a very different light.

Whether the Pupil Premium has improved the life chances of poorer pupils is also a moot point. Ofsted reports on the effects of the policy are a mixed bag.

The education watchdog says the policy “is making a difference in many schools” – but it notes that the gap in attainment between children who get free school meals and those who don’t has failed to close significantly.

The Lib Dems also said in their manifesto that the money should be used to cut class sizes. Under the coalition, the average secondary school class has shrunk very slightly but primary class sizes have gone up a bit.

VAT rise

Almost as embarrassing as tuition fees. Senior figures happily posed in front of billboards screaming about a TORY VAT BOMBSHELL.

The material was still on the Lib Dems’ website when the coalition announced in its first budget in June 2010 that VAT would rise from 17.5 per cent to 20 per cent.

The bigger picture: This one can’t be blamed on coalition horse-trading. Both the Conservatives and the Lib Dems denied they wanted to raise VAT before the election, before abruptly changing their minds.

Lords reform

The Lib Dems wanted a fully elected House of Lords. The Conservatives said they favoured a “mainly elected” second chamber.

The coalition agreement promised to “establish a committee to bring forward proposals for a wholly or mainly elected upper chamber on the basis of proportional representation”.

The 2012 Lords Reform Bill looked more Conservative than Lib Dem: it envisaged a second chamber about half the size of the Lords, where about 80 per cent of members would be elected.

In the end the coalition dropped plans for a crucial vote on the issue, fearing a rebellion by Tory backbenchers would force a defeat.

The bigger picture: Labour joined with Conservative rebels to help derail the Bill, despite calling for reforms to the Lords themselves.

Special advisers

The coalition agreement promised to “put a limit on the number of” Spads, the notorious Westminster class that once counted Messrs Cameron, Miliband, Osborne and Balls among their number.

In 2009 the Lib Dems were saying: “These are political jobs, and should, therefore, be funded by political parties. Special advisers will not be paid for by the taxpayer.”

In 2013/14 the coalition was employing were a record 103 special advisers, compared to 71 in 2009/10. The cost to the taxpayer has gone up from £6.8m to £8.4m. Nick Clegg alone has 20 advisers.

The verdict

A string of broken promises here, not all of them attributable to the Lib Dems being in a coalition. And there are bound to be things that FactCheck has missed.

That’s not to say the party has achieved nothing in government, although it’s inherently difficult to list policies wholly attributable to the Lib Dems, since we can’t listen in on coalition negotiations that take place behind closed doors.

The party’s supporters often claim the credit for making sure the government has kept its promise to keep overseas aid spending at 0.7 per cent of GDP, setting up a Green Investment Bank and scrapping ID cards. But all these things were in the Conservatives’ 2010 manifesto too.

Other policies undoubtedly bear the Lib Dems’ fingerprints: free school meals to all under-sevens; the Green Deal; delaying the renewal of Trident.

The very first pledge in their 2010 manifesto was to raise the tax-free personal allowance to £10,000. This week’s budget saw the announcement of plans to raise the allowance to £11,000.