Tony Lloyd: For Labour MPs like me, there is one big question - were we lied to about Iraq?

Clearly, no weapons means no legal base. As things stand, this war was illegal and unnecessary in its stated purpose

There will always be a profound moral case for the international community, given legal sanction by the Security Council of the United Nations, to topple dictatorships like Mobutu in the Congo, Suharto in Indonesia or even Saddam in Iraq. But this was never the stated intention of the United States or the United Kingdom in Iraq. The frenzied attempts at the UN to get a second resolution were not designed to get a legal basis for regime change but were more limited to the removal of weapons of mass destruction. Indeed when the Foreign Secretary, Jack Straw, opened the debate on a likely war with Iraq, he told the Commons: "The Cabinet has decided to ask the House to support the United Kingdom's participation in military operations, should they be necessary, with the objective of ensuring the disarmament of Iraq's weapons of mass destruction, and thereby the maintenance of the authority of the United Nations."

If that was the aim of and legal base for war, it is no wonder that people are questioning why we have not yet found and destroyed anything of significance. Jack Straw has said that these weapons may never be found, although presumably he believes they are there somewhere. The Prime Minister is more optimistic: the weapons will be found but it will take a long time and the priority now is humanitarian and political reconstruction.

But this same Prime Minister warned before the war, "[There] is a powerful and developing threat that the world must face - the risk is that states such as Iraq, which are proliferating these chemical and biological weapons of mass destruction, will combine in a way that is devastating for the world with terrorists who are desperate to get their hands on those weapons to wreak maximum destruction."

If we really believed that Saddam controlled weapons of such enormous threat, now that they are under nobody's control we should surely be scouring every garden shed, every kitchen cabinet, to ensure we reach these weapons before al-Qa'ida gets there first. Or am I being alarmist?

The cynics will prefer to believe that Donald Rumsfeld had it right when he introduced us to the idea that the WMD had all gone before the war. This may not be a big problem for the Bush administration but it is most certainly an enormous difficulty here.

Our government was under enormous pressure when it could not deliver the second resolution at the UN. Ministers were forced to reiterate the twin propositions that Saddam had WMD and that resolution 1441 gave a specific justification for military action on the basis of that possession. Huge efforts were made to convince a sceptical public. Trust us. Trust the Americans. It is no secret that when Parliament debated and voted on the war, those Labour MPs who expressed doubts were treated to an almost unprecedented demand for solidarity with the Government - threats, promises and, of course, the seductive argument that the Government must know something or they would not have let things get this far. Trust us. Trust the Americans.

Clearly, though, no weapons means no legal base. Put simply, as things stand, this war was illegal and unnecessary in its stated purpose.

For Labour MPs that period was one of the most difficult times I have known in Parliament. The instinct to support a Labour government was put to the test by the enormous cynicism expressed by the public and party members about American motives for going to war. MPs fell out with their local parties and put their reputations on the line. They are entitled to be angry if they have been merely bit players in Donald Rumsfeld's war games.

The problem now for us all, both the public and members of Parliament, is to know whether we were accidentally misled or lied to, and by whom.

In the end, only an inquiry into the competence and probity of the security services, and the way in which the intelligence they provided was used, is going to restore the nation's trust. Without that, it is the authors of war within the Government whose credibility is on the line.

Tony Lloyd is a former foreign minister, and Labour MP for Manchester Central