Philip Webster (left), Political Editor of The Times, explains how a classic parliamentary ambush - and Tony Blair's dash home for supper - led to a Government defeat

"There's massive egg on the faces of both Hilary Armstrong, the Chief Whip, and the Prime Minister. Downing Street has tried to minimise this today - saying it won't happen again - but even Number 10 has admitted it was an extraordinary cock-up.

"Ms Armstrong's future has not been discussed in Number 10 today but that doesn't mean to say that she will escape a reshuffle. It may be that Mr Blair is not calling for her head because ultimately if he had stayed there would not have been a problem.

"The latest information, which I was given last week, is that Mr Blair was planning to put the reshuffle off until after the education and health votes ... it is possible that it will now be brought forward to put a new Chief Whip in place before these votes. If that were to happen, Geoff Hoon would be the obvious choice as replacement.

"There's certainly a question mark over her future although there may have been in any case. With Tony Blair preparing to hand over to Gordon Brown in the next two years I would have thought the next Chief Whip would be agreed between the two of them.

"The Conservatives are jubilant. It is becoming clear today that they tricked the government with a fairly clever 'under the radar' operation.

"Before last night's vote, the Tory leaders agreed with the Government that the whipping arrangements on both sides would be a two-line whip. This is a step down from the top-priority three-line whip under which all MPs are compelled to attend.

"The Tories were putting it around that they were happy with the concessions that had been made to the Bill. It was only when the Commons began to fill up with Tory MPs that the government's whips started to panic. By then it was too late.

"The Tories had quietly told their MPs to turn up - and almost all of them did. All but 11 were there and those who did not attend were properly paired off with government MPs who were also not able to attend. The Tories mounted a brilliant whipping operation and caught the government napping.

"The government lost the first amendment vote by ten votes. We don't know why Blair was given leave of absence but after that he cleared off, presumably back to Downing Street although No 10 has refused to say.

"Presumably, the government whips had decided either that after losing by ten votes there was no way of turning it around, or that the Tory rebels had made their point and would not vote against the second amendment. Either way, they were wrong and Mr Blair's absence meant the Government lost by one vote when it could have won.

"As to whether this puts the rest of Blair's reform agenda in doubt... there weren't that many rebels last night. There were only 21 Labour MPs who went against the government and they were the usual suspects - Bob Marshall-Andrews and the crowd who always vote against Labour. So the whips managed to contain their own rebels but lost the vote because of a cock-up.

"Downing Street has refused to say what Mr Blair did after leaving the Commons. He may have had an official engagement but it's far more likely that he went back to Number 10 to have a bite to eat with Cherie and the kids. His voting record is not the best of a serving Prime Minister."

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