I’ve pre-recorded an interview for BBC Radio 4’s The Week In Westminster this morning. Back in the days when I was almost a journalist, I used to present the programme myself, so I was in the same Millbank studio, joining Danny Finkelstein for the two of us to be quizzed by Steve Richards about whether the Tories have really changed under Dave. Danny says they have, I say they haven’t, at least not much beyond style and presentation.

There is a lot to be said for Danny. At least he has been on the other side of the fence, having worked for the Tory Party under John Major and William Hague. More importantly, he wrote a good piece on politics and the internet for my edition of The New Statesman. Still more importantly, he said on his Comment Central blog that my interview with Alex Ferguson was so good he read it twice. And most important of all, he does the Fink Tank in the Times, required reading for all football statto saddos.

So even though we disagree about Cameron, it was a pleasant way to spend part of Thursday morning. I know from my Culture Show experience (BBC spin machine starting to crank into action by the way, at http://www.bbc.co.uk/cultureshow/ ) that these programmes can be touchy about what and when you give away in advance. But I don’t suppose it will surprise too many of you to hear Danny was defending Dave, and I was not.

When you get to the heart of what the defence is, it is basically that Cameron has changed ‘the tone’ of the Tory Party. I don’t doubt that tone is important, but under Big Change Tone, aka TB, we had by this stage of his leadership changed an awful lot more than mood music. Constitution, strategy, policy on the economy, tax and spend, unions, public services, defence, constitution … etc.

Danny’s other main point was that Labour under TB learned on the job, and did not have all the skills required on Day 1. There is something in that. But we did by this stage, for all the focus on the five specific pledges, have a pretty clear programme for government. If the Tories were to produce a specifics pledge card now, what would it say beyond the vague tone-changes which in any event vary from day to day, as we have seen in his inconsistent approach to the environment?

Cameron is hugely helped by the bias in the media which takes nothing Labour says at face value, and yet allows the Tories to come up with the most vacuous nonsense without ever putting it under sustained scrutiny, which plays right into his ‘bob, weave, bob, weave’ issue to issue, that’s another day got through ‘strategy.’ (I use the word, though what he does is not strategic, because I can think of no other at this time of a beautiful sunny morning.)

This argument about whether he has done enough to change the Tories, whether he really understands policy, and frankly whether he and his colleagues work hard enough, must surely become more central to the political debate. We are talking about someone who, if the polls don’t change, is the next Prime Minister. Yet despite having been leader of the Opposition for several years, it is hard to work out what kind of PM he would be, and what in policy terms he would do.

What is interesting from recent focus groups is that the word ‘lightweight’ is now popping out unprompted from many more mouths than before. Interestingly, his intervention on the BBC licence fee went down badly, not because people wanted to defend Jonathan Ross’s salary, but because they want to hear the Tories on the economy, and what they would do, as opposed to their constant bleating about what Labour does. So as so often, I think the public are ahead of the political pundits on questions that really matter.

There was a skirmish around this question arising from The New Statesman. Political reporter James Macintyre had a dig at The Spectator’s Fraser Nelson who, when asked by Macintyre to say where Cameron had changed policy, said the areas were ‘too numerous to mention,’ yet failed to back it up. Fraser, in an otherwise splendidly positive assessment of my editing skills, for which Merci, hit back, and now the Fabians have offered a platform for the two of them to debate this as detailed on http://www.labourlist.org/admiral_nelson They should take it.

It might not be quite as elegant and sophisticated as my chat with Danny and Steve, but it is an argument that will become more and more important to the pre-election skirmishing. And the fact that Danny kept saying that Dave’s biggest achievement was the change in tone suggests it is an argument Labour can win. Provided, as I say in the New Statesman (final plug of the day) editorial, they start to put him under sustained pressure.