Tony Blair's Labour followers have always claimed to be the wing of the party which cares most about winning.

Certainly under Blair's leadership that was always the case. Whatever you think of the man, he won three successive elections for the party - something no other Labour leader has ever managed.

However, since Blair's departure, this desire to win seems to have totally deserted his supporters and the man himself.

David Miliband's defeat to his brother in 2010 was a huge surprise for most commentators, yet it was wholly predictable. Miliband had the Labour leadership in his hands yet threw it away out of an arrogant refusal to move towards his party's own supporters.

His successor Liz Kendall has taken a similar and even more election-losing trajectory. She began her campaign by winning gushing plaudits from right-wing papers and is set to finish it with the support of little more than one in ten Labour supporters.

A new YouGov poll out today puts her in a distant fourth place. If a fifth MP had made the final shortlist, Kendall would probably now be a distant fifth. The fabled Blairite ability to win no matter what seems to have entirely vanished. As Blair admitted himself today, if the route to victory meant tacking left, he would not take it. For the Blairites, purity has triumphed over victory.

To understand why things have gone so badly wrong, you only needed to listen to Blair's speech this morning.

Blair remains an excellent communicator. On any measure, he looks and sounds like a credible leader. Though keen this morning to emphasise the importance of politics over personality, it is undeniably the case that voters looked at Blair and saw a natural prime minister.

Without that charisma, he would never have won three elections. Whatever Blair says now, Labour didn't win because of great public enthusiasm for the public finance initiative. They won in large part because Blair appeared as a credible prime minister and his Tory opponents did not.

However, when you actually look at the message, rather than the messenger, it becomes clear that increasingly little substance remains in the Blair project.

To demonstrate my point, let's take a read of the final passage of Blair's speech today. This is a fairly typical extract and you can find similar passages in many of Blair's or David Miliband's speeches and articles over the years.

"We won not because we did what we thought was wrong as a matter of principle but right as a matter of politics; but when we realised that what is right as a matter of policy is right as a matter of principle. "Labour shouldn't despair. We can win again. We can win again next time. But only if our comfort zone is the future and our values are our guide and not our distraction."

Now it is possible, if you are willing to spend the time, to tease at least some sense out of the first of these paragraphs. After extensive analysis it's just about possible to discern a vague shadow of an idea about principles and power.

However, the final paragraph is essentially meaningless. Blair could have rearranged all of the words and made an equal amount of sense. If he had instead told the audience that 'our future is our values and our comfort zone is our distraction', nobody would have blinked an eyelid. It is a slogan in search of an idea. The words are stitched together almost at random, like embroidered patches on a blanket. It is without any understandable meaning. It is gibberish.

If any other politician had come out with a sentence like that, they would quickly become a laughing stock. The fact Blair has made an entire career out of similar pronouncements, shows just what political ability he still has.

However, it also demonstrates the vacuity of the style of politics he first created and which politicians of all political persuasions have since sought to emulate. Asked today what he would say to a Ukip voter worried about immigration, Blair quoted the Institute of Chartered Accountants slogan "skills for growth and opportunities for all". Now it's very hard to argue against this slogan. After all who wants skills for recession and opportunities for no-one? However, it's difficult to see it as a rallying call capable of persuading many Ukip supporters to desert the charms of Nigel Farage.

And it is precisely this vacuity which has led to the rise of parties like Ukip and to a lesser extent the SNP. When British politics has become the equivalent of a slogan designed by chartered accountants, there will always be space for those with clear ideas spoken in plain language. You may not agree with banning immigration or breaking up the UK, but you can at least understand them as ideas.

This is also the reason behind the remarkable rise of Jeremy Corbyn. Today's poll puts Corbyn in first place in the Labour leadership race with a whopping 17% lead over his nearest rival Andy Burnham. This is already being written about as a great indictment of Labour members. This view was articulated by Blair this morning, who said that if your heart is with Jeremy "you should get a transplant".

But rather than blame the Labour electorate for the rise of Corbyn, the party should instead look at the paucity of the alternatives. If any of Corbyn's rivals had even a sprinkle of star power or political vision, then Corbyn would be nowhere in this contest. Corbyn is winning precisely because Labour supporters understand who he is and what he wants and don't understand the same of his rivals. When Corbyn says he is against austerity and then votes against welfare cuts, Labour supporters understand that position and can choose to either back it or not. When Burnham says he's "firing the starting gun" against welfare cuts and then chooses to abstain on a vote authorising them, people have basically no idea what or who he really stands for.

As long as Labour continues to speak and think like chartered accountants, they are doomed to lose. As George Orwell once famously wrote: "If thought corrupts language, language can also corrupt thought." Blair was a brilliant political leader. However, his biggest legacy is a style of political language and thought which has made obfuscation easier and political vision harder. As a result of this approach to politics, the public are more distant from politicians in general and Labour in particular than ever before. If Corbyn becomes the next Labour leader in September, a large deal of the credit should be laid at Blair's own front door.