Labour and the Liberal Democrats have long shared a common progressive agenda. From taxation and public spending to the importance of education, democratic reform, Europe and the environment, more has united than divided the centre left. Those values often desert Lib Dem activists locally. Yet nationally our shared agenda has been so close that at times it seemed we might heal the tragic division in the centre left that enabled the Tories to dominate government for so much of the last century.

Nick Clegg changed all that (and is a timely lesson for Labour on the importance of who is elected leader). Peter Hain repeatedly warned of the Lib Dem drift to the right and the potential consequences for Labour of Clegg’s own Orange Book revolution. The Lib Dem leader’s decision to throw his lot in with the Tories is nothing to do with electoral arithmetic but a desire to make common cause with those closest to his own heart. For Clegg’s activists, to paraphrase Tony Blair, it’s worse than they think – he actually believes in this.

Clegg’s party remains progressive at heart and knows he has sold its soul for a clutch of second-tier cabinet posts and questionable influence. With David Laws’ personally unfair departure from government, he doesn’t even have a single true believer alongside him in cabinet. Simon Hughes’ election as deputy leader, as the conscience of the Liberal left, demonstrates the widespread concern even in his parliamentary party.

Clegg turns somersaults with his language to reassure his party, but talking of ‘progressive cuts’ makes them nothing of the kind. The reality is that this government’s progressive deficit is vast and Progress is right to target it through its Red Wedge series.

The coalition’s progressive deficit begins with their approach to the economy. The Lib Dems fought the election as part of a global progressive consensus that it was through fiscal stimulus that we would best weather the storm and do most to protect jobs, businesses and the fabric of our society. As Clegg said, ‘merrily slashing now is an art of economic masochism. If anyone has to rely on our support, and we were involved in government, of course we would say no’. He now says things are worse than he thought. This is a lie exposed by the government’s Office of Budget Responsibility assessment that the bulk of the deficit would have been wiped out by Labour’s own plans and their prediction that debt will be some £30 billion lower across the parliament. Nobel Prize winners Paul Krugman and Joseph Stiglitz warn against cuts and former Monetary Policy Committee Danny Blanchflower describes George Osborne’s Emergency Budget as ‘totally unnecessary and wildly dangerous’. The respected Chartered Institute of Personal Development estimates the spending squeeze will consign 750,000 public sector workers to the dole queue, taking unemployment to nearly 3 million.

Yet the cuts will go ahead because it is a right-wing, ideological hatred of the role of government itself that drives these reductions. It is the Lib Dems doing the Tories’ dirty work, signing up to economic madness that will see unemployment cause spending on welfare to rise and tax revenues to fall.

Yet Clegg still talks of ‘progressive cuts’. There is nothing progressive in axing the Future Jobs Fund, cancelling 40,000 jobs for young people, when the LibDem manifesto pledged ‘a work placement scheme with up to 800,000 places’. Neither is stalling Labour’s industrial activism, which is critical to stimulating private investment and creating jobs. It isn’t progressive to kick away the ladder of opportunity provided by a university education from 10,000 young people. Or cutting £300 million from initiatives for young people including funds to reduce teenage pregnancies and get 16 and 17-year-olds to stay in education. Cuts to the Building Schools for the Future programme and plans to ‘refocus funding from Sure Start’, despite all those election denials, are not progressive. Nor is Michael Gove’s decision to abandon Labour’s extension of free school meals. A progressive government wouldn’t ditch house-building targets and reduce local authority funding leading the National Housing Federation to estimate affordable homes built this year will slump by 65 per cent.

In other areas the Lib Dems have chosen impotence. Norwich South, won with only 310 votes, would not have a Lib Dem MP without the pledge to vote down tuition fee increases. Yet, in comically sinister terms, the Coalition Agreement says ‘arrangements will be made to enable Liberal Democrat MPs to abstain’ as if they are all to be sent away on a fact-finding mission, perhaps in search of their principles. They will also abstain on reintroducing the married couple’s tax allowance, the renewal of Trident and the building of new nuclear power stations (although they have laughably won the right to speak against before abstaining). If Labour looked again at a graduate tax, alternatives to Trident and put renewable investment before nuclear, it would not only be doing the right thing, but would massively destabilise the Lib Dems.

On Europe we have the extraordinary sight of Clegg accompanying William Hague to the continent, presumably deploying his language skills to translate Tory euro-hostility into something politer. What became of his accusation in the debates that Cameron had allied himself in Europe with ‘a bunch of nutters, anti-Semites and homophobes’? On immigration, a plan for earned citizenship for illegal migrants, a progressive idea worthy of exploration, turns into support for a cap on non-EU migration (despite the unskilled already being barred).

Scrapping the Human Rights Act would not be new politics, but the Tory desperation to do so is only thinly disguised by the Lib Dems’ agreement to ‘investigate the creation of a British Bill of Rights’ to replace it. A commitment to localism is undermined by a central government-imposed two year council tax freeze and the removal of democratic accountability from schools, while Michael Gove personally dictates a new history curriculum from Whitehall. Elected police chiefs sound democratic but are populist not progressive. Even on democratic reform, they have secured little for the sacrifice of their independence. The voting system referendum will only be on the non-proportional Alternative Vote and the Conservative machine and wealth will campaign against.

With only nine per cent of their voters identifying as being on the centre-right or right, the dangers for the Lib Dems of this bonfire of progressive polices is clear. The Fabians’ Tim Horton has calculated the 18 Lib Dem and 38 Conservative seats vulnerable on modest swings from Lib Dem to Labour.

To ensure the party is best placed to take advantage of this opportunity Labour must ‘rediscover our sense of progressive mission’ as Ed Miliband has put it. That mission should put at its heart the gap between rich and poor, support for a living wage, addressing pay differentials in the private as well as public sector and defending the new top rate of tax. It should recognise that affordable housing and employment protection, not tougher immigration laws and rhetoric, will address voters’ feelings that the system is against them. It should reclaim civil liberties for the left and, if it really wants to rip this coalition apart, support AV+ which is proportional while protecting the constituency link.

If Labour can reconnect to those who felt we strayed from our ideals in recent years, and elects a leader that has the most appeal to previous Lib Dem voters, we can win and it will be the Lib Dems who suffer most at the ballot box. The tragedy is that so many people across our country will have to suffer first.

Phil Taylor was a Labour special adviser from 2001-2007 and is a former director of Progress. He is currently a member of the senior leadership team at a secondary school.