The rise in Lib Dem support since the TV debate is the best thing that can happen to this election. Oh ok, a sudden ten point rise for Labour, matched by a Tory slide, would have been better, but it was never likely, so this is a good second best.

It means finally there is the chance of making it a policy based campaign in which the public get the chance to hear, from the parties talking about themselves and each other, and via the media, what the different policy positions are.

Surely even our trivialising, process-obsessed broadcasters can see that if they have any sense of public service left in them, this election now has to be about policy, policy, policy.

Because we have moved from everyone thinking David Cameron was home and dry, and so the talk was of what a Tory government would be like, to a position where anything can happen.

According to the bookies Cameron is still favourite to be PM. But the very thought is now, finally, unsettling people. GB can still do it. Or there could be a hung Parliament, with either Labour or Tory as the biggest party.

There was a touch of the X Factor to the leaders’ debate set-up. And Nick Clegg very cleverly played the anti-politics card from the position of being there on equal terms but with nobody, him included, thinking he could be Prime Minister. But both Tory and Labour now have interest in openly recognising the hung parliament scenario. Because it is that which means that for once people really do have a right to know what Lib Dem policies are, and how close or distant they are from Labour and Tory. If they can be big time players, they have to be treated as such.

Of course on lots of things, Labour and the Lib Dems agree. On a few things, the Tories and the Lib Dems agree. I suspect many of those people who are now expressing support for Clegg based on his TV performance are unaware that he wants to cut child trust funds, child tax credits and winter fuel payments. Or that he wants to scrap the train to gain programme. Or that he wants an amnesty for illegal asylum seekers.

Traditionally third party leaders have not been exposed to anything like the policy scrutiny of the other two leaders. In the years leading to this election, the Tory leader has also not really been scrutinised.

What happened on Thursday is that the Tory leader stumbled badly under the weight of examination by the other two. Now Clegg, who struck people as a more attractive and younger ‘time for a change’ candidate than Cameron, has enjoyed a surge in support, which means his policies will get more attention.

We should all welcome that.  Because when we get to May 6, the issue for all the undecideds must surely be economic and policy credibility as we face an uncertain future. And I think Labour will be seen to score best there.

According to a former colleague of mine who advises the Lib Dems they did not expect to be in this position one week in.

It is bound to make the Tories nervous and so it should. It should not make Labour nervous. We should welcome it, and feel confident that just as we have begun to beat the Tories on the merits of arguments put and sustained over time, we can do the same with the Lib Dems, whilst all the time reminding people this shows the progressives outnumber the conservatives in Britain, by a long way.

That in itself is a measure of how much New Labour has changed Britain for the better.

*** Quote of the day from Cameron btw ‘We all know that polls react to news cycles. It is a very depressing thing about politics: you do your manifesto launch or conference speech and you get a bounce and you think ‘fantastic, we are on our way’ and then a few days later you think ‘hold on, what did we do all that for?’

So now we know why, within 24 hours of launching The Big Society, it became The Great Ignored – ignored, that is, by him. It is a very revealing statement, further confirmation that he thinks more about the news cycles than he does about having a clear vision based on clear prnciples and thought through policy positions … which is why he came such a cropper on Thursday.

May I also point out to our still-biased media that if Kinnock, Blair or Brown had ever mistakenly slipped China into an answer on why we need nukes, they would by now be so stoking the frenzy that the UN would have to have an emergency Security Council meeting. He is still getting away with the tamest media environment of any Opposition leader in history with the possible exception, for a day or two, of Nick Clegg.

*** Buy The Blair Years online and raise cash for Labour http://www.alastaircampbell.org/bookshop.php.