Blair cannot stand comparison with Attlee. And his time is running out...

The old gibe about the empty taxi drawing up and Attlee getting out resonated with many in his own party at the time

Well, what would "little Clem" have made of that? As Tony Blair rather easily escaped the tentative clutches of Iain Duncan Smith in the House of Commons yesterday it was hard to imagine something less reminiscent of the driest, most laconic, and unobtrusive Prime Minister in the history of the office. If anything, the Blair performance - with its repeated challenge to the Opposition leader to say whether he agreed with the constitutional changes at the heart of the row that has rumbled on since last Thursday - was more reminiscent of the lawyer tap-dancing his way out of trouble in Chicago: "Give 'em the old razzle-dazzle."

The pipe-smoking Clement Attlee wasn't a man for razzle-dazzle. But the reason the comparison has suddenly become so tempting is that Mr Blair has just made it himself. He began his Fabian lecture on Tuesday by pointing out with just a hint of irony that much of the left was rather slow to see the splendours of the man it now almost universally regards as having ushered in "the new Jerusalem".

Which is true, of course. The old gibe about the empty taxi drawing up and Attlee getting out resonated with many in his own party at the time, exasperated almost as much by his lack of charisma as by what they - usually wrongly - saw as his insufficient commitment to socialism. He was no stranger to rebellions on the left, in and out of the Cabinet, particularly in relation to foreign policy and defence. And the limerick he wrote about himself said a lot about the disdain in which he had long been held: "Few thought he was even a starter/ There were many who thought themselves smarter/ But he ended PM/ CH and OM/ An Earl and a Knight of the Garter."

And there were similarities, however accidental. Both men were strongly pro-American in outlook, able to relate to a Republican US president. And just as doubts have arisen about Blair's influence in Washington, so there were about Attlee's. Did his famous dash to the US really stop Truman using the atomic bomb during the Korean war? Both were educated at what we wrongly call public schools. Both were personally weak on economics. And history would show that even Attlee wasn't wholly immune to one of the more damaging charges laid against Tony Blair by Clare Short on Tuesday. As Professor Peter Hennessy has pointed out, it was Attlee's own decision in 1947 initially to keep discussion of the British A-bomb away from the full Cabinet, believing as he did that "some of them were not fit to be trusted with secrets of this kind".

But in style they - and their times - could hardly have been more different. You can't exactly imagine Cherie Blair driving Tony Blair around in a Ford Focus, or whatever is the modern equivalent of the little Prefect in which Violet Attlee used to chauffeur her husband during election campaigns. Nor is there much in common between this most media-savvy of prime ministers and the one who famously refused to instal a news agency machine in No 10 until his press secretary, Francis Williams, pointed out it would carry his beloved cricket scores. He might, too, have made a better job of last week's reshuffle, being regarded as "the best butcher" in the business by Harold Wilson. One unfortunate, aghast to be sacked, was told: "Not up to it, I'm afraid."

But none of this, of course, is why many in the Labour Party regard the comparison between Blair and Attlee as sacreligious. For six years after the Attlee landslide, his admittedly exhausted ministers had presided not only over the nationalisation of the Bank of England, but of the railways, waterways, mines and iron and steel, and the end of empire in India, Pakistan and Burma, co-operation in the Marshall plan and the creation of Nato and, above all, the setting up of the National Health Service. History has correctly judged the Attlee government as genuinely hegemonic; the settlement - the bad as well as the good - was not unravelled until Margaret Thatcher. How can Blair compare with this?

The counter-argument is that Blair and Brown - as mighty a weight relative to his boss, if a much less protective one, as Ernest Bevin was to Attlee - have made the Bank of England independent, introduced the minimum wage, presided - unlike Attlee who was faced with a debilitating devaluation crisis in 1949 - over a strong economy; have started, however slowly, to rebuild public services degraded by what Blair on Tuesday called the "progressive deficit" of the Thatcher-Major years; gone some way towards redistribution; introduced some overdue liberalising social legislation, and embarked on the biggest programme of constitutional change in more than a century.

There is much in this. But there are caveats. The last of these points is particularly instructive. For Attlee's contradiction was that he did unconventional things in a highly conventional way - being as Professor Hennessy has insightfully written, "the most left-wing prime minister Britain will produce in policy matters and the most socially conformist in personal ones".

To take a topical example, he would probably not have tampered with the Lord Chancellorship even if he had gone on and on - for no better reason that it might have got in the way of matters he regarded as more vital - among which incidentally, the eccentrically irrelevant passion for banning fox-hunting among modern Labour MPs would certainly not have been one. That isn't at all to say that it's wrong to do; only that a prime minister who was never that personally keen on - say - devolution and isn't at all interested in a democratic Lords, has a slightly bigger job than he would otherwise do convincing the country it is worth the candle now rather than -say - after the next election.

But the real question is much bigger than that. Not many governments totally change the weather for a long, long time. The Asquith-Lloyd George continuum did. Attlee did. Thatcher did. The Blair administration still just might, not least if it finally settles Britain's destiny in Europe and genuinely sorts the public services so that no one in the foreseeable future attempts a privatised alternative. This is a huge task, and Blair is certainly right that not all the necessary methods pay homage to Labour's household gods.

The unions have their part to play - from ending restrictive practices, to loosening their centralised grip on pay bargaining and accepting that, within clear and important limits, private means can help to achieve public goals. But he still has to convince the left that his passion for "choice" helps not just the middle classes, who might otherwise go private, but the poorest who just want their local schools and hospitals to work.

This is work in progress. Maybe it could still end up lastingly changing the weather. Blair's government remains in a much stronger electoral position than Attlee's was after six years. But the hourglass has turned. Time has now started to run out.