By Nick Assinder
Political correspondent, BBC News website
It apparently took hours of agonising before ministers came up with a form of words aimed at heading off a defeat over Iraq, while appearing not to cave in to opposition demands for a fresh inquiry.
Mr Blair has rejected holding an inquiry while troops are in Iraq
It took only seconds for Defence Secretary Des Browne to blow it all apart by declaring immediately after the Commons vote that there would be an inquiry when the time was right.
So unequivocal was his answer, and despite government attempts to play it down as a slip of the tongue, the prime minister has now himself admitted he is not ruling out a future inquiry.
So, the tantalising question is - if either had said such a thing before the Commons vote, would the Tories have dropped their opposition and allowed Mr Blair an even larger victory?
Some of a suspicious nature have already suggested that ministers had calculated the Tories were opening themselves up to potentially damaging allegations of hypocrisy by demanding an inquiry after supporting the war.
So, they claim, the government was happy to let David Cameron lead his troops through the lobbies with Labour rebels and Scottish and Welsh nationalists and attract the sort of headlines he received in the following day's newspapers.
Whether that is the case or not, Mr Browne's comment put the pressure firmly back onto the government, and the prime minister was forced to concede in question time that there might well be another inquiry in the future.
And that has seen Mr Blair accused of finally caving in to opposition pressure .
In the hours leading up to the Commons debate, the prime minister's official spokesman insisted that agreeing to the demands for an inquiry would send out the wrong messages to British troops - and send the wrong signal to "the enemy".
Browne said an inquiry would come
But he also said lessons from the conflict would be learnt and that there would come a time when it would be appropriate to "look back".
In the debate itself, Foreign Secretary Margaret Beckett went a bit further by declaring: "There will come a time when the issues will be explored in the round."
In other words, the message from the government to Labour rebels was that they need not worry, once the troops were home - and, presumably, under a new prime minister - there would be a Falklands-style inquiry into the war.
The message to the nationalist parties and Tories, however, was that they were undermining British troops in Iraq by attempting to rake up all the old arguments over the war at a particularly difficult and sensitive time for that country.
But then, as the government celebrated its victory, Mr Browne declared: "When the time is right, of course there will be such an inquiry."
Spokesmen immediately declared Mr Browne had made a slip of the tongue and that the government position was as set out by Mrs Beckett in the Commons.
Others believed the defence secretary had simply forgotten the carefully crafted government script and let the cat out of the bag.
Either way, what had been a difficult, but ultimately successful night for Tony Blair led only to further questions and a distinct change of line from the prime minister himself.