The tide finally turns for Tony Blair

We seemed to have reached some kind of turning point for Tony Blair this week. The Guardian newspaper, which has for years exercised the role of critical friend to Mr Blair, finally pronounced that the time had come for him to go. Some Labour figures such as Helena Kennedy were baldly stating the same thing for the first time. The language was vivid, albeit still in private, among loyalist Labour MPs in the backrooms of the Commons.

The "Bye-Bye Tony" case was carefully constructed. The benefits of Mr Blair staying are now outweighed by the costs of him delaying his much-trailed departure. He has done the big things. Britain's presidencies of the G8 and EU are over. The Olympics have been won for London. And he does not have the time - having said he would not serve a fourth term - to stay the course on Israel and Palestine, the entry of Turkey into a reformed EU, or the implementation of the Gleneagles pledges on Africa.

The war on terror and the mess in Iraq will outlive him. At home, Mr Blair has become a liability rather than an asset on schools and NHS reform, and now on Labour party funding. "Carrying on simply because he can", The Guardian said, "will begin to look self-indulgent. . . Every day he stays in the post, the government's standing is eroded: the unity of the party, Labour's effectiveness in Parliament and, above all, the public trust are all damaged while he's there."

What is most interesting in this long litany is not that Mr Blair is being undermined by complex controversy on policy, such as education reform. It is that what has proved the final straw for his former allies is the secret loans scandal.

What the small political advantage was, at the time, to Labour in keeping these donations quiet by asking for them as loans is not clear. But whatever it was is outweighed by the damage their exposure has now caused. Labour has tried to limit this with new proposals to ban secret loans to parties in future, and there is talk that the day of state funding for politics draws ever nearer.

But changing the rules is not the answer. New systems will throw up new problems. Whatever the rules, crafty people will find a way round them. They might channel donations through relatives. They might set up a Friends of Tony Blair charity. They might come up with something even more ghastly, like the US system, which ensures that the required spend is so high that only millionaires can run for office, disenfranchising huge sections of the electorate.

The philosopher Onora O'Neill, in her Reith lectures in 2002, considered the business of trust. She said we live in a culture of suspicion, which tries to put in place ever more stringent rules and forms of control to counter our growing mistrust. But these new kinds of accountability, she concluded, serve only to reinforce that sense of distrust. They also give a kind of sanction to those who think that, as long as they stick to the rules, they are doing enough, whatever breaches of the spirit lie behind them. All of this sounds familiar to any reader of the New Testament.

What is so damning for Mr Blair is the revelation that individuals such as Dr Chai Patel had been happy to make donations, but had been persuaded to make a loan, in order to avoid having to declare it as a gift under election law. The intention to obfuscate, if not actually to deceive, is glaringly unavoidable. That is why Labour's proposals - and those of other parties - cannot solve a crisis that is rooted in trust. What people want is not new rules, but a new prime minister.

Paul Vallely is associate editor of The Independent.