Tony Blair has yet to testify before Sir John Chilcot's inquiry into the Iraq war, but he must already be squirming after the first week's evidence. Contrary to expectations, the mandarins have not pulled their oh-so-elegant punches. Freed from obligations of loyalty, they appear to be addressing the fundamental questions. Germany's Angela Merkel and France's Nicolas Sarkozy must be congratulating themselves on their choice of EU president. Had they been blinded by Mr Blair's stardust, the presidency would already have been badly tarnished.

On day one, we learned that British officials picked up the drumbeats from Washington soon after George Bush's election but had dismissed overthrowing the Iraqi leadership because "it had no basis in law". Sir Peter Ricketts, a former chairman of the joint intelligence committee and now the top official of the Foreign Office, said that up until March 2002, Whitehall distanced itself from regime change. Just one month later, Mr Blair told Mr Bush that he would support military action "to bring about regime change".

On day two, the inquiry heard how Mr Blair was told 10 days before the start of the war that Saddam's weapons of mass destruction had been dismantled. In the run-up to war, ministers were repeatedly told of "huge gaps in intelligence". This contrasts with Mr Blair's foreword to the September 2002 dossier in which he wrote that the intelligence had established "beyond doubt" that Saddam had continued to produce chemical and biological weapons. In fact, there was plenty of doubt.

Then came Sir Christopher Meyer, former Washington ambassador, who said that Blair's government had decided up to a year before the invasion that it was a complete waste of time resisting the apparently inevitable, but that there could have been a different outcome had Mr Blair succeeded in delaying the invasion by withholding British co-operation. Not all of these accounts should be taken at face value. Some, such as Sir Christopher's, could be self-serving. But few would doubt the integrity or weight of the judgment that Sir Jeremy Greenstock, Britain's ambassador to the UN at the time of the war, delivered yesterday. Revealing that he had threatened to resign at one stage, he said he regarded Britain's participation in military action as of questionable legitimacy, in that it did not have the backing either of the majority of UN member states or of the majority of people in this country.

No one is on trial in this inquiry, although it might hear evidence that could be used as a basis for criminal prosecution. Nor should all of Britain's misfortunes in Iraq be blamed on Mr Blair. What is already clear from the first week alone is that the decisions, secret or otherwise, that led to war were the product of systemic failure. Intelligence analysts, diplomats, in fact the entire machinery of the British government, proved supine against Washington's will. Under that pressure, almost everyone buckled. Few in the Foreign Office woke up to the revolutionary effect of toppling a Sunni Arab regime, of which Iran would be the chief beneficiary. This in itself is a major analytical failure, the consequences of which the FCO is having to grapple with to this day.

The lingering question is not what went wrong in Iraq, but whether the disaster could be repeated. Next week Barack Obama will commit the US to a troop surge in Afghanistan, a decision in which Britain will once again be in lockstep. At the same time, plans are now being laid to ratchet up UN sanctions against Iran. Neither the US nor Britain has kicked the intervention habit, and the conflict in Iraq is also far from over. So what confidence is there that another major military escalation in Afghanistan is based on sound intelligence, judgment and analysis? The chilling aspect of this week's evidence is that it sounds not so much a description of the past but the present.