But there are people that have played pivotal roles who should be given the chance to put their views across - not about the war as such but about Britain's diplomatic and war record. I'm thinking of senior US officials, from President Bush down the hiearchy but also then-French President Jacques Chirac, former UN chief Kofi Annan and so on.
I'm not suggesting Sir John Chilcot broaden his inquiry to nor that 'W' would come to give evidence. But given that so much of British strategy - and Blair's defence - relates to what others, like the French government, thought and did it at the time would seem sensible to ask at least former French President Chirac to give written evidence.
I would love for Monsieur le President to hop across the Channel and tell us why he was unconvinced about the US and British WMD intelligence and what conversations he had with Tony Blair. He probably won't come. But given the international character of the Iraq War, and the extent to which the British government's pre-war actions were shaped by other governments, it seems a little odd to rely only on British players.