They may have been speaking without notes, but the first speeches after the official announcement of the campaign represented an important moment, and the party leaders will have thought long and hard about every word they said.

So what we can gather from those speeches are the key arguments, and also the tone, of the campaign to come. I did not make an exact count of ‘five more years of Gordon Brown’ but it was the single biggest theme that came from David Cameron. It was the only phrase to draw a cheer from party supporters gathered around him, apart from a message of support for the troops in Afghanistan, a sub-Kennedyesque reference to asking what we can do to make our society better, and the end.

There was a lot of talk of hope, optimism and change, and the projection of energy is clearly a a big thing for the Tories, but I would say if there was one driving message, it was a negative one about Labour rather than a positive one about the nature of the change they promise. I also noticed once more his glib reference to ‘this regional  nonsense,’ which I hope was spotted by every non-Tory candidate in the country. If anything shows up his near contempt for the idea that government, central or regional, can make a difference to economic or social success or failure, that was it.

All campaigns are a mix of positive about yourself, negative about your opponents, and record. The sense building of the two main party manifestoes is that there will be more substance and more content to the Labour one. I know I am biased, but I think that accurately reflects the way the policy debate has developed in recent weeks and months.I can only assume that the Tory pre-briefing, suggesting a marriage tax allowance is the centrepiece of the manifesto, is deliberately misleading and they have a lot more lined up for the day of the launch.

GB’s main message on the economy can clearly be seen both as a positive or a negative. Only Labour can be trusted to secure the recovery – note the seniority given to Alistair Darling in his positioning in the grouping of ministers behind GB – or, put negatively, the Tories are a risk the country cannot afford.

But I felt that in both public services and political renewal, there is the scope for greater argument around more substantial proposals from Labour than the Tories. That will matter as the campaign unfolds.

The team element was important to the tone too. The Tories will say GB is presenting himself as the leader of a team because he lacks the qualities needed to carry the fight to Cameron alone. But whereas the leaders are hugely important, and even more so in this campaign because of the TV debates, the public know they are electing a government not just a PM. There was a lot of experience and judgement, as well as a few authors of bright ideas for the future, lined up behind him today.

Cameron is not as popular as he was but remains more popular than his party. When he talked about speaking for the ‘great ignored’, quite a few of the most ignored people in the country are in the shadow cabinet, and he is the one ignoring them because the less they are on TV the happier he is.

But if he wants to present the race as being all about him, not only does he risk the notion developing that they are a one-man band,  but it falls even more on him to spell out the detail of the change implied in all the words and slogans today.

I know this was not the time for that. Today was indeed about themes and tone, and the manifestoes will be the means by which the detail is set out.

But what I took from this morning is that Labour have more to gain from positive campaigning than the Tories, which is not a bad place to start, provided a bit of good old-fashioned Tory-bashing takes place alongside it.

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