An examination technique I learnt early as a schoolboy was to go for an arresting general claim whenever hazy about the facts or the logic. This is a technique that Tony Blair has devoted a lifetime in politics to honing and it was on display again on Thursday night when at Westminster Cathedral he delivered his lecture “Faith and Globalisation”.

Oh boy, did he globalise. Oh boy, did he evangelise. And so we are naturally tempted - those of us who remain doggedly unconvinced of the ragbag of metaphysical claims made by the world's religions - to respond in general terms. Already friends have been in touch urging me to attempt a humanist avaunt-ye-Godbotherers counterblast. Sock it to him!

It's tempting. But the world, the media, and his own country, have for too long indulged Mr Blair by countering his passionate abstractions with counter-abstractions. And that has suited him beautifully because in a clash of abstractions nobody ever wins. Passion checkmates passion but never trumps it, and he saunters away, eyes cast up like Joan of Arc at the stake, crying: “I only ever did what I truly believed to be right.”

Looking sadly back over the trajectory of this charming imposter's delusional career, it grows clearer to me that, short of the policeman's knock, there was only ever one way Mr Blair might have been stopped early in his tracks. It was not by answering passion with outrage - but by asking quietly for the transcript.

Then, after scrutinising each sentence calmly, we could have reached for a red ballpoint and marked his homework as a chalk-flecked history master might. Small marginal comments and questions - “define your terms”, “what's your evidence there?”, “but how do you square this with * (above)?” and (time and again) “what does this mean” - will, with patience, eat through the gaudy fabric of a Blair oration like an army of moths. Sadly, this is not the kind of thing that either a rowdy Commons Chamber or the modern mass media are geared to do, and Mr Blair has traded on that all his life.

And this stuff from Westminster Cathedral on Thursday really was lower-sixth. It is clearly Mr Blair's own work. It doesn't reach undergraduate standard and should never be allowed to detain a proper don, but perhaps it may detain me.

So please arm yourself with a red ballpoint, and go first to his justification for Alastair Campbell's famous phrase that at Downing Street, “We don't do God”.

Why not? “To admit to having faith,” Mr Blair explained, “leads to a whole series of suppositions, none of which are very helpful to the practising politician. First, you may be considered weird.” [Marginal note: but "blessed are ye when men shall say all manner of evil against you, for my sake" - Mat v II. How reconcile w. duty of Christian witness?]

“Second,” Mr Blair continues, “there is an assumption that before you take a decision, you engage in some slightly cultish interaction with your religion...” He goes on to give absurd examples of policies where wrongheaded people might think religion guided his hand [Marginal note: but see yr. para. 9 above: “If you are someone ‘of faith' it is the focal point of belief in your life. There is no conceivable way it wouldn't affect your politics.” How reconc.? Abortion? Divorce? Homosexuality? Human Fertilisation & Embryology? Helping the poor?]

“Third,” he goes on, “that you want to impose your religious faith on others. Fourth, that you are pretending to be better than the next person.” [Marginal note: but reconc. w. yr. para. 38 below: "Let me be clear. I am not saying it is extreme to believe your religious faith is the only true faith. Most people of faith do that"?]

Or, as he reminds us near the end: “I make no claims to moral superiority.” [Marginal note: ditto. Is saying "I belong to the only true faith" while adding that this "only true faith" centrally informs your politics, not a claim to moral superiority? Explain.]

I could go on, but why bother, because the speaker is at heart so unsure of what he wants to say that the speech remains in the shallows and says very little. Prominent among those shallows, however, is one idea heard often and typically from the milder sort of Christian, Hindu or Liberal Jew.

Real, “positive” faith, said Mr Blair, would “encourage peaceful co-existence by people of faith coming together in respect, understanding and tolerance, retaining their distinctive identity but living happily with those who do not share that identity.” [Forgive me one more marginal note: how reconc. respect, understndg, tlrnce, etc, w. “ours the only true faith” - para 38?]

Mr Blair is encouraged by this, he says, not least because (he believes) faith is newly resurgent in the 21st century. He rejoices at that - why, “even ten years ago religion was still being written off as a force in the world”.

Well, he's right on both counts. First, the “positive” approach to inter-faith relations is indeed well represented in many religions, and a certain kind of nice Anglican has been banging on about it all through my lifetime. Second, it's true that there do seem to be religious revivals under way across the globe.

The problem for Mr Blair's analysis is this: where faiths are reviving, they are tending towards fundamentalism and intolerance. Even in the Catholic Church, it's the reactionary bits that seem to be the most muscular. Likewise the US Bible Belt. Not to speak of Islam. The two halves of Mr Blair's argument (1: faith advancing - hooray! And 2: faiths can be tolerant - hooray!) are therefore at war with each other.

But the bedrock of Mr Blair's argument is that, worldwide, faiths have more in common than divides them, and that they are all, in an important sense, on the same side. And you know what? He's right - but not in the way he thinks he is.

Throughout history, faith resurgent, the Church militant - be it Islam, Christianity or Judaism - tends as it gains enthusiasm to become more extreme. It goes back to basics. It strips the modifications of modernity, delving for a core. That core is fundamentalist. So, yes, from the Bible Belt to the Vatican, from the West Bank to Helmand, a comparable muscle is being flexed, it is profoundly reactionary, and all faiths do share it. In some deep and inchoate way, these human tendencies are indeed “all on the same side”.

But it's not my side, and it shouldn't be yours; and a secular political class of the kind that produced our current generation of leaders, including Mr Blair, Gordon Brown and David Cameron, should think long and hard before throwing so much as a scrap to this tiger - let alone riding it.

Plainly Tony Blair does believe in God. A political career showered with good fortune has proved that God believes in Mr Blair, so perhaps Tony judges it only polite to return the compliment. But there, for all our sakes, the exchange of pleasantries should end.

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