At a q and a I did last week, someone asked me what made Tony Blair nervous. ‘Big set piece speeches,’ I replied, instinctively.

I’ve thought about it a bit more since, and I think the instincts were right. My diaries record several instances of him saying, before Budget debates in Opposition, or Queen’s Speech debates in Government, that if there was anything more nerve-wracking, he had yet to find out what it was.

I remember when he was due to speak to the French National Assembly in March 1998. I don’t think I had ever seen him so nervous. Partly that was because he had decided to have the speech translated so that he could deliver it in French. But it was also because, no matter how experienced a politician may be, there is something particularly challenging about making speeches to a group of all-party politicians from another country.

There is also something about the great historic political venues, particularly when surrounded by ritual and tradition, not to mention the booming drums that beat in rhythm as he walked towards the Paris chamber, that cranks up the pressure any big speeech brings with it.
It was the same when he spoke to the joint houses of the US Congress, even if he had a lot more experience by then. The little nervous tics that enter any speech-writing process, not to mention in the immediate run up to the speech with all the last-minute checks and concerns about protocol, get exaggerated as the tension builds.’Is my tie straight?’ ‘Is there water by the podium?’ These are probably no more than subconscious expressions of the scale of the event.

It is impossible to be in the place where Gordon Brown will be on Wednesday, as he stands to follow Churchill, Attlee, Thatcher and Blair, and become the fifth British Prime Minister to address both Houses, without feeling both the history of the setting, and the daunting nature of the moment.

In my weekly email to supporters of Go Fourth, the campaign for a Labour fourth term, I urged them to try to watch the speech in full. Even though it will be extensively covered on the news, there is something about these big moments that for a proper understanding requires the whole event to be followed. Reading the text is not enough either. You need to hear the tone, see the reaction, feel the mood and above all try to grasp the bigger argument that political leaders always try to have in their more important speeches.
It comes at an important moment for both of our countries.

In common with every country in the world, the shared agenda is the economic situation and the need to make sense of what has happened in the past as the world tries to shape a better economic future.
It would be hard, and indeed inappropriate, for Gordon to be overtly political. But I think that what is emerging from the choices being made by Labour in Britain, and the new Democrat Administration in the States, is a shared progressive agenda to lead the world out of recession into recovery, with the values of the centre left being more relevant to the new economic order to follow than the values of the right which to a large extent got us into this mess in the first place.

When Tony Blair spoke to Congress, the backdrop was Britain and America standing together in the face of international terrorism, and two wars being fought in Afghanistan and Iraq. What tomorrow is about is America and Britain standing together in the face of an economic challenge that is global in scale and will require a global response to match.

How Gordon pitches that argument, and the response it generates, is more than a question of speechcraft. It really matters. Given how much, he would not be human if the nerves weren’t jangling a little. But once that first warm growl of appreciation comes back at him from the packed benches, those nerves will settle, then what counts is the history, the argument, and the specific proposals he puts forward.