“Peace Hath Her Victories, No Less Renowned Than War.” (John Milton)

I was there, with my wife and daughter. So were many other good folk we saw getting on the train at Rayleigh, and more than a million from all over the UK. We walked with the Lib Dem march from the Royal Festival Hall, across Westminster Bridge, round Parliament Square, up Whitehall, and eventually arrived, some hours later, at Hyde Park. We missed Charles Kennedy, but we caught Jesse Jackson and Ms Dynamite.

The effect was stunning. We are told that people are not interested in politics, that the young are ‘switched off’, that the apathy party wins. But there we were, one chilly Saturday in February, making our views known – ‘the mother of all focus groups’, as one commentator described us.

There were all sorts there. Pacifists, who reject war under all circumstances. Kurds and other Iraqis, who think that war may be the only way to free their country – but don’t believe the time is right. People of profound faith, and people with no particular belief, who just don’t trust our Prime Minister.

Charles Kennedy, the Lib Dem leader, showed remarkable courage appearing on the platform in Hyde Park. It could so easily go wrong. The US is hell-bent on a war, come what may; and if everything goes well for the Americans and whatever allies they can muster, it might all be over in a week, and the world would soon forget the tortuous path we are currently treading.

But Kennedy and the Liberal Democrats won’t be swayed by such pragmatic thoughts. The case for war has not been made, and we have the self-belief to stand up to Blair’s “Trust me, I know what I’m doing” approach.

It is not clear that Iraq possesses weapons of mass destruction. It is not clear that they intend to use them. It is not clear that the inspection process is useless. There is room for doubt in all these cases – unless you are Mr Blair. Even the most aggressive hawks in the US administration have toned down their assertion that Iraq has links with Al Qaida – there is just no convincing evidence.

The UN inspector, Hans Blix, asks why there is such a hurry. Eight years with inspectors in Iraq. Four years without. Now twelve weeks with them back in again – and Blair and Bush can see no alternative to war.

There is no doubt that Saddam Hussein is a nasty piece of work, and that Iraq (and the rest of the world) would be better off without him.

Blair has done his case no good by switching his argument from the need to control Iraq’s armoury to the moral case for getting rid of Saddam. This has highlighted the weakness of the first argument – for if Iraq poses a real threat to our security then we have no alternative but to act robustly in our own defence. It has also underlined the shakiness of the moral approach, as religious leaders in this country and abroad have made clear their doubts about the current Anglo-American war fever.

One of the things the Lib Dems are concerned about, but which does not appear to feature strongly in the Prime Minister’s views, is what happens after a war. American plans are sketchy, to say the least, but seem to be based on leaving the current ruling Ba’ath party in charge in Iraq, under the control of a US Army General.

Here again, the weakness of Mr Blair’s arguments become apparent. If Saddam’s regime really is so intolerable that we have no option but to intervene militarily, then the last thing we should do is remove the head and leave the body. We must be prepared to replace the whole corrupt system of government. This means creating a whole new framework of international law, since regime change for its own sake is quite illegal under current international law.

We should also ask ourselves whether military intervention in the middle east will make the world a better place. My view is that an attack on Iraq, led by two Christian leaders from the western world, will sow seeds of resentment which will bear unwelcome fruit for centuries to come. Will bombing Baghdad make a repeat of September 11th more or less likely?

As I write, our Prime Minister has reportedly been stunned by the extent of opposition to his pro-war stance in the House of Commons. 52 Lib Dem MPs, with rebels from Blair’s own party and others, have inflicted a historic humiliation on the government. He should listen to them. He should listen to us.