Is this messy resignation a sign that Mr Blair is losing control of his Cabinet?

It is significant he chose to go early, creating a sense of reshuffle chaos, rather than cooperate with the Prime Minister

The political season opens with a cabinet resignation. Andrew Smith may not have been a household name, and his brief, Work and Pensions, was not the most glamorous. There was even speculation that Mr Smith would have lost his job anyway in the ministerial reshuffle being planned for later this week.

The political season opens with a cabinet resignation. Andrew Smith may not have been a household name, and his brief, Work and Pensions, was not the most glamorous. There was even speculation that Mr Smith would have lost his job anyway in the ministerial reshuffle being planned for later this week.

Even so, this is a messy development for Tony Blair at best, and could turn out to be more significant and damaging than that. At the very least, Mr Smith's decision illustrates that Mr Blair has lost the art of neat ministerial reshuffles. In his statement last night, the former minister said he wanted to spend more time as a constituency MP. In which case, why could Mr Smith not have waited a few more days until the formal reshuffle? I am sure his constituents could have managed without his complete political attention for a little longer.

It is highly significant that Mr Smith chose to go early, creating a further sense of reshuffle chaos, rather than cooperate with Mr Blair and offer to resign when he announced other ministerial changes. I am not suggesting that the parallels are precise, but Mrs Thatcher's later messy reshuffles were a sign that she had lost authority over her ministers, that she was no longer fully in control. Mr Blair's reshuffles are now chaotic affairs.

Mr Smith had run out of patience with Downing Street, reading stories in newspapers about him that he was not up to the job and that he was about to be replaced. It is also true, and not surprising, that he wants to spend more time in his marginal Oxfordshire constituency, but Mr Smith's decision was much more complicated than that.

He is a close ally of Gordon Brown. The Chancellor knew of Mr Smith's intentions before Mr Blair. Mr Smith told the Chancellor at around 12.30pm yesterday that he planned to go. He saw Mr Blair an hour later. Understandably, the Prime Minister spent some time trying to persuade him not to act in this way. When it was clear that Mr Smith was determined to resign, there were extensive negotiations about how he should explain the reasons for his departure, with Downing Street eager to make them as bland and innocent as possible. Again it seems that Mr Smith did not wish wholly to cooperate.

Apart from concerns about his constituency and resentful fears that he might be sacked, there were other factors. In policy terms, Mr Smith was fighting a battle with Downing Street over further crackdowns on incapacity benefit. He supported a range of measures limiting expenditure on this benefit, but was opposed to imposing a time limit on incapacity benefit for over 50s, who he regarded as genuinely needing the cash, and other proposals aimed at reducing the amount that some of the more elderly disabled received. He became angry about newspaper reports that suggested he was being old Labour in his approach when he had been one of the pioneers of welfare to work - a central New Labour policy area, albeit one shaped by Gordon Brown.

Even if this were the end of the story, it would not amount to very much; a relatively unknown and politically vulnerable cabinet minister in a marginal seat suddenly going, possibly before he was pushed. But as is often the case with New Labour, there is a symbolism that is sometimes at least as important as the substance. When Tony Blair contemplated a return to the Cabinet for Peter Mandelson, he planned to give him Mr Smith's job. He and Mr Mandelson regarded welfare policy as an area in which the Government had failed to be radical. One of the reasons that summer reshuffle never happened was the degree of resistance Mr Blair faced over making such a move. In particular, Gordon Brown regards welfare policy with a keen interest and has been the driving force behind the reforms that have taken place.

Now it is as if the summer break had never happened. Apart from the suntans, the only difference is that the former Health Secretary, Alan Milburn, has replaced Peter Mandelson, as the subject of heated ministerial exchanges. As has been widely reported, Mr Blair wants to make Mr Milburn the party chairman. Mr Milburn is a strong media performer and would possibly improve the erratic performance at Labour's main headquarters, no longer the smooth Rolls Royce machine it once was.

But Mr Blair's desire to make the appointment is an interesting reflection of what he takes to be his new found political strength. Earlier in the year, he considered giving Mr Milburn and Stephen Byers informal roles in the build-up to an election campaign. The three of them agreed that this would be too nebulous. So Mr Blair has decided to risk another almighty row with Mr Brown and, indeed, John Prescott by placing Mr Milburn in a formal position at the heart of the next election campaign.

As with the departure of Mr Smith, the symbolism of this matters. Mr Blair would be asserting his authority over all those who are questioning what he is up to. But there are also significant matters of substance. Mr Milburn seeks a radical Blairite manifesto, although he has not yet fully defined what he means by this. The Brownites are pretty clear what he means. They suspect a further shift to the right, meaning that a third term will be marked by further battles over policy.

There are three ways in which events will develop. It is quite possible that in the pre-election atmosphere, Mr Smith's absence will be smoothly filled and Mr Blair will decide not to push matters too far. Mr Milburn would spend more time with his family. This would be a painful illustration of the limits of his powers, but would avoid further turbulence for now. Equally, it is possible that Mr Blair, who is in a determined frame of mind, could press on with Mr Milburn's appointment and there could still be little public fuss with the election looming.

But I doubt if it will be as neat as that. Mr Smith's resignation is a sign of a certain ministerial restlessness. The decent and unassuming Mr Smith is not a trouble-maker, and yet he has caused trouble. In a more minor key, it is almost as unlikely a development as Sir Geoffrey Howe making waves. Mr Blair could not carry out a reshuffle in the summer partly because he faced too much ministerial discontent over his plans. Now ministerial discontent forces him to focus on a reshuffle slightly earlier than he had planned, and in less calm circumstances.

Mr Smith was a New Labour figure, but from a Brownite perspective. This is the current danger facing Mr Blair. New Labour is now split into at least two different camps, with policy differences in some cases as important as the inevitable tensions over personalities and conflicting ambitions. The most important divide in British politics is not between new and old Labour, but between those who all regarded themselves as "new" in 1997. Perhaps the prospect of an election will impose an artificial unity, but there has been little coming together behind the scenes this week, the first that most ministers have been together at Westminster since the start of the summer break. This is not the start to a new political term that Mr Blair would have wanted.

s.richards@independent.co.uk