So what exactly have the Liberal Democrats done since they took power?

They claim they're providing a social conscience and making a difference in government. Is it true? Oliver Wright investigates

(Getty)

It is a message relentlessly hammered home in every speech, every press release and every interview given by Liberal Democrat ministers at conference: the party is making a difference in government.

Without the Liberal Democrats, so the argument goes, a Tory Government would have no social conscience. It would cut the deficit but at the expense of the poorest and most vulnerable. Without the Lib Dems the NHS would face privatisation and the green agenda would remain just that – a vague promise without hard policy. But how true are the claims?

Bringing more of the lowest paid out of tax

The Coalition agreement says the Government will move towards setting the income tax threshold at £10,000 by the time of the next election and so far the threshold has been raised by £1,000 to £7,475. This was a key Lib Dem demand and if they had not been in power it is highly unlikely that it would have been pursued by the Tories, who are ideologically more interested in cutting taxes for the middle classes than for the very poor. Lib Dem effect: 5/5

Changing the NHS reforms

The Lib Dems like to trumpet this as one of their greatest achievements in Government. Without them, they say, the controversial NHS reform Bill would have been pushed through without changes – leading the way to the effective "privatisation" of the NHS. This is disingenuous. The Bill was changed because the medical profession revolted and public opinion was overwhelmingly negative. The Lib Dems objected but it was Mr Osborne and David Cameron who decided to change the Bill when they realised how damaging it was to the Tory brand. But they allowed the Lib Dems to take much of the credit. Lib Dem effect: 2/5

Same-sex marriage

The Lib Dem Equalities Minister Lynne Featherstone has announced plans to allow gay couples not just to have civil partnerships but to "marry" as well. The party quickly claimed the initiative for themselves leading to angry exchanges with the Tories. In fact, Downing Street said it was David Cameron who pushed for the change. Lib Dem effect: 3/5

Taking on the banks

The Tories have always been susceptible to lobbying from the banks and big business. Without the Lib Dems in Government it is likely that the Tory response to the Vickers report into banking reforms would have been more muted. The Lib Dems have been effective in putting pressure on the banks to lend more to small businesses and Vince Cable's sabre rattling has helped stiffen George Osborne's resolve. Lib Dem effect: 4/5

Pupil 'premium'

Giving extra funding for pupils from the most disadvantaged backgrounds was a proposal that was in both the Conserva- tive and Lib Dem manifestos – although the Lib Dems claim the Tories stole the idea. However the Lib Dems place far more emphasis on the scheme and it could have been delayed if the Tories. had won power outright. Lib Dem effect: 3/5

Europe

The Government has been remarkably level headed on Brussels – resisting calls from the Tory backbenches for a tougher, more isolationist approach. The Lib Dems have made it easier for Cameron to resist the pressures from his own party. Alone, Cameron would have found this harder. Lib Dem effect 4/5

Inquiry into phone hacking

Despite the initial bungled attempt by Vince Cable to get News Corp's bid for BSkyB blocked, the Lib Dems have been influential behind the scenes in framing the Government's response to phone hacking. Despite not having a minister in the Department of Culture, Media and Sport, Don Foster has liaised closely with Jeremy Hunt and Nick Clegg was influential in pushing for tough terms of reference to the Leveson Inquiry. Lib Dem effect: 2/5

Tuition fees

Raising tuition fees was in neither party's manifesto – the Tories didn't mention it and the Lib Dems were in favour of a graduate tax. It is arguably the case that if the Lib Dem leadership had not been prepared to tackle student funding and vote against their own promises then fees could never have been raised. An achievement in Government certainly – but not one they would necessarily trumpet. Lib Dem effect: 4/5

Green deal

Will allow people to install double glazing, loft and wall insulation and other structural improvements to boost the energy efficiency of their homes without having to pay upfront. The money will be got back later through the savings on heating bills. Overall the Green agenda of the Government has been more radical than if the Tories were governing alone – a fact emphasised by its commitment to tough carbon reductions targets. Lib Dem effect: 3/5