Two bulls are standing in a field, eyeing up some cows on the hillside. The younger of the two bulls says excitedly: "Let's run up the hill right now and shag one of them!" The older, wiser bull replies: "No, let's walk up the hill - and shag the lot of them."

The gag was a favourite of Tony Blair's immediate predecessor, the late John Smith. One of the wisest old bulls around, he was a "long-gamer", sometimes to the frustration of impatient people around him (that perky young Blair, that cocky guy Straw). Smith drew two lessons from the randy bulls: one, there was no point wasting energy if you had serious business ahead of you; and two, running around making a big fuss could scare off the very people you were trying to, er, win over.

Next month will mark the tenth anniversary of Smith's death. But only now are some details of his life coming to light, thanks to his authorised biographer, Mark Stuart, who gave an early taster of his work at the Political Studies Association conference in Lincoln just before Easter.

Stuart's biography - which will be out by next spring - will not make comfortable reading for Blair and the myth-makers of the new Labour machine. The portrait will be of a serious and committed man who would probably have led Labour to victory without the unease, rancour and division that characterise the party today. Not that Stuart will join the fashion for historical what-iffery. "Smith would have found all that ridiculous," he says.

Stuart, also a Scot, sees Smith as a true son of the Highlands who had "something of the clan chieftain about him". Support him and you were likely to benefit from his warmth and kindness. Cross him and you'd be shoved up against a wall.

Jack Straw can confirm this. In early 1993, as is well known, Smith reacted furiously to Straw's persistent attempts to open a debate on Labour's old Clause Four. Stuart has unearthed the details of the two men's final, hour-long meeting on the subject. It ended with Smith hurling Straw's pamphlet at its retreating author with the words: "And you can take this f***king thing with you, too!"

Smith did not see the need to alter Clause Four, arguing that it held only symbolic and sentimental value. Nobody thought it described what a future Labour government would do. Besides, as Smith told an aide: "You can't make people change everything all of the time." Not a very new Labour attitude, that.

Much more important to Smith was one member, one vote in the party, which he pushed through at the 1993 conference. Stuart argues that this, not the Blairite razzmatazz around Clause Four a year later, was the significant step that put Labour back on the path to power.

Stuart's book may help put to rest the new Labour mythology, which states that the party was heading for only the most uncertain of victories under Smith. Labour's repositioning on tax, for example, began in 1992, not 1994. And for all the glitz of new Labour's campaigning, the knockout blow to the Major government was delivered by Smith in the Black Wed-nesday debate in 1992, when he described John Major as "the devalued prime minister of a devalued government".