The media keep saying that the Labour leadership election ‘has failed to capture the public imagination’, though how they define this judgement is entirely subective and based in  large part on an understandably bigger interest in the coalition, they being the government and all that.

Yet in recent weeks, and particularly in recent days, I would reckon that ‘Ed or David?’ has gone to the top of the list of questions posed by random passers by as I go about my business. There is a genuine interest in who wins this afternoon, because people understand we could be talking about the next Prime Minister, and we are certainly talking about the person who will lead the political debate against and about the coalition.

So it matters. As to the answer, I have maintained the position throughout that I hope it is David and I think it will be David. I have nonetheless been around long enough to know that bookmakers don’t get a lot wrong, so the closing of the gap in the odds, and Ed finally moving to a very narrow favourite, underlines that it is no foregone conclusion.

This is a difficult day for the five contenders. The votes are all in. The result is set and there is nothing they can do about it. And though it is widely accepted there are only two who might win, the results for the other three are not just about pride.

They will all be working out what to say, and how to handle themselves, according to the various scenarios that are possible. But for all of them, one central message has to go out to the public – that an essentially internal debate is over, now a very different kind of political debate begins.

Our system depends in part of a strong Opposition engaging in constant political battle, not always unfriendly, with the government. Both sides need that debate to be interesting, enervating, significant, so that the public engage fully in it too.

But the public, or a large proportion of the public, do not follow every twist and turn. Far from it. For the government, it is never that difficult to get attention, to set an agenda, to frame the outlines of debate. On the issue of the deficit, with Labour conducting its own debate, they have had a fairly easy ride. They have managed to persuade a lot of people that the cuts are needed. Labour has to persuade people that some of the cuts are needed, but that with George Osborne more in the driving seat than people realise, the scale of cuts has moved through neccessity into ideology.

But what won’t work is a catch-all na-na-na-na-na objection to every cut the coalition make. What could work are the big arguments about economic and social changes required to rebuild confidence in a vision of government founded on values that set Labour apart from their opponents. 

Despite the unfortunate timing of the announcement – football and all that – this is one day where people will notice Labour, and know that an important decision is being made. It is a day for Labour to start to set out those big arguments. The detail can follow, not least in the leader’s speech in a few days time.

Past leaders used to have all summer to work on their conference speech. David or Ed will have a couple of days. Days which have to be used to set the terms of a debate that will define the next election.