The progressive wing of the Lib Dems broadly supports the coalition and the agreement underpinning it: because we welcome co-operative politics; because we saw that the arithmetic did not allow a coalition with Labour; because we recognise that not everything about Cameron's Conservatives is toxic or illiberal and because we know that we can get some Lib Dems policies and values put into practice.

But the leadership must not get too comfortable with the current government setup. Our party will need to fight the next election on a distinctive, radical and progressive manifesto.

Some say we will also be fighting the next election on a joint record of achievement with the Tories. We must reject that. Whatever the benefits of ministerial solidarity and collective responsibility for government stability; whatever the perceived populist benefits of pretended total unity, at the next election we must communicate clearly those coalition achievements that we supported and those we did not. It is essential to the voters' understanding of what the Lib Dems stand for. That message cannot be delivered in a four-week election campaign. Work must start now. We need closer identification of Lib Dems in parliament, in the media and in government, with those coalition plans that are Lib Dem-inspired and, conversely, some distancing from Tory-imposed policies.

The party voted to endorse the coalition agreement, but we did not vote to endorse the implementation of illiberal or unfair government policies that have emerged since. The party must help Nick Clegg and his colleagues resist those by communicating our unhappiness in the same way the Tory right does about some of our proposed policies.

Nick has rightly rejected electoral pacts with any other party at the next election. But we need to go further. We must rule out any pre-election preference for future working with any other party. We will have been in government with the Tories in this parliament and our ministers will feel varying degrees of comfort about it. But that means nothing in terms of future potential coalitions. In fact, we must make sure that we are in a position to "dock" with the Labour party if the parliamentary numbers work and there is relevant policy overlap – regardless of what a wounded Labour party is saying now.

Nick has done a good job for the party and in government, but he has made one major error: the talk of "fair cuts". Cuts in public spending on the scale needed (or at least envisaged) are never going to be truly fair or progressive. That is an economic and statistical fact of life. It would be under Labour as well. It is clear that Lib Dem influence will make the cuts fairer than they would be under a Tory government, but it is fundamentally wrong to claim they will be fair. Going down that path leads to the deputy prime minister disputing an Institute for Fiscal Studies analysis of the budget with an article headlined, "Fairness should never be a numbers game". There must be objective measures of fairness if politicians are to be accountable. If you don't want a statistical analysis of the budget then don't make statistical claims of fairness for it. The red book claims that the budget was progressive in that it hit the rich more than the poor. It did not. Given that it included £11bn of welfare cuts, it was an achievement that it was not any more regressive than it was.

Strategically Nick really needs to be a little less didactic and somewhat more sensitive to his party's ideological constituencies. To say as he did in an interview on Saturday that "The Lib Dems never were and aren't a receptacle for leftwing dissatisfaction with the Labour Party" is factually wrong since many Lib Dem members and voters in recent years have come from the left of a Labour party that has lost its way on peace, social justice, nuclear weapons, inequality and civil liberties. All are classic leftwing issues within the Labour movement, even if we see them as central within our own tradition. But worse, it amounts to a rejection of some of the activists who are sustaining the party. At a time when political parties seek to be broad churches in their appeal if not in their platform, it would be perverse if one party leader appears to want to reject new supporters. Perhaps he meant to say that the Lib Dems never were and aren't merely a receptacle for leftwing dissatisfaction with the Labour party, or that we should not seek to position ourselves in the future merely to be so (a outcome the coalition formation has done rather well at achieving in any case). It is the role of Simon Hughes, as deputy leader, to seek assurances on this point.

The majority of the members and activists in the party, in rural and urban areas, in the north and the south, are and remain anti-Conservative in their political outlook and philosophy. The party respects and admires Nick but he does not have a blank cheque.