Comment is Free carried this by me yesterday. Already the argument is intensifying. What's important is not to be too obsessed about what the Lib Dem policies are or are not but to encourage the public energy for reform - which has settled upon them as the only way to make a breakthrough. I consider what ther acceptable terms for a coalition of the centre might be, which connect to Stuart's and Sunny's posts of yesterday on the same issue. There seems to be quite a lot of agreement between us so far, whether this is significant in any way remains to be seen.

On Sunday, Gordon Brown said historians would record his approach to the Lib Dems so far as "an attempt to get them involved in what I call a progressive consensus". I don't know about historians, but as far I am concerned, while I'd welcome a realignment on the left, it is now inconceivable this could be led by Gordon Brown.

The reason why he pursued this appeal to the Liberal Democrats is because of the huge potential increase in their support. We want to remind ourselves what is driving it. When Labour attacked the Conservatives over the influence of Lord Ashcroft's millions, William Hague told the House of Commons: "People in glass houses shouldn't throw stones". Two weeks later, when David Cameron demanded an inquiry into former Labour ministers putting themselves up to hire, Lord Mandelson replied: "People in glass houses shouldn't throw stones".

According to Monday's ICM poll, commissioned by Power 2010, "Ninety-six per cent believe it is important that the next government cleans up politics and reforms our democracy". That's everybody. Those 4% who don't agree probably didn't hear the question or were lobbyists.

But it is not going to happen if the two-party duopoly continues. It could, however, start to change if there is indeed a Lib Dem breakthrough. The welcome possibility of a hung parliament could be a historic opportunity to begin the real reform of our democracy that voters now demand.

The two big parties will collaborate in a dance of the undead to belittle Clegg and the Lib Dems, and intimidate the public to prevent this.

It's important that the Lib Dems keep pressing home the larger picture, confident of the fact that both a traditional conservative belief in the need for honour in public life, and a progressive view of the need for reform, now point to the need for a government led by them. Also, if Tory supporters determined to stop Brown, and Labour ones desperate to stop Cameron, sense that the Lib Dems could achieve this – and that a vote for them is no longer a wasted vote in our godforsaken system – Clegg and Cable could come through the middle. It certainly seems possible that they may hold the balance of power.

In which case, we also need to ask what should happen next.

As the Conservatives reject constitutional reform, this will demand a coalition of Labour and the Liberal Democrats. As it is possible that Labour will have more seats in the Commons and therefore claim the post of prime minister, even if the Liberal Democrats get more votes, we need to be clear about the conditions that would make a realignment coalition legitimate:

1. Any such result will be a defeat for the leadership of Gordon Brown and Peter Mandelson and they must resign – the country would not accept them as part of a coalition government. "The people want something different."

2. The new government should immediately pass the Liberal Democrat's freedom bill in the form of a great repeal act that protects liberty and dismantles the incipient database state, including a repeal of the digital economy bill.

3. Stop the Trident replacement programme

4. Put the reform of the electoral system to a referendum, which includes an informed choice of one or more proportional systems and not one limited to Brown's alternative of either the status quo or AV.

5. Given that the House of Lords is half of our parliament and must be replaced, the Commons isn't working, the demand for local power is growing, and that both Labour and the Liberal Democrat manifestos call for a written constitution, the new government should create an independent constitutional convention representing all voters, to propose how we arrive at a new settlement.

The latter is needed because the central and probably all-consuming task facing the new government will be the economic crisis, brought about by New Labour's embrace of America's financial model. But the opportunity for reform must not be lost as it is this that will give any coalition its legitimacy. Therefore the bulk of the reform programme needs to be given space and authority outside of the pressing routines of government.

The next two weeks represent the chance of a lifetime for long-needed political reform. The dark powers of the status quo, the deep state, the Murdoch press, the weak-kneed worriers in the BBC's hyper-paid executive suits, the naysayers of the boardrooms and editorial conferences, will do everything they can to snuff it out.

The SDP had a similar moment in 1981 to 1983. But it was in large part a media creation from above, the Establishment still believed in its institutions and Thatcherism provided an alternative strategy. This time we are witnessing what seems to be a genuine electoral insurgency from below, while Whitehall's self-belief, a vitally important bulwark for any regime, has slipped away – and with it, its unmatched power to destroy any challenge from outside. While neither main party has any alternative strategy.

This is why the Lib Dem breakthrough, driven by popular demand for an end to the new corruption, can succeed and why, if successful in electoral terms, it could then go on to reform Britain.