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The Twyford gospel choir swayed from side to side. “Take control!” they sang, in perfect harmony. Oh no, I thought, don’t encourage him. For somewhere, lurking in the transepts of St Paul’s Cathedral, Gordon Brown was waiting to preach (sorry, speak) to us on the eve of the blessed G20.

“Hallelujah!” cried the choir. Truly, this must be Gordon’s idea of heaven. No one in Labour treats him like this any more. The press were on high, at angel height. We had a perfect view of the Prime Minister, son of a manse, as he began his sermon.

And lo, but he was loud. The Prime Minister, standing beneath what may be the most glorious dome in the world, boomed forth. As one bellowed word overlapped the next, I felt that even God would have to turn down His hearing aid.

For Gordon, this was a deeply revealing speech. A Presbyterian by nature and nurture, he remains chary of religious fervour but, for him, the global economic crisis is a morality tale that needs telling and retelling. His role seems to be that of a Moral Maze Moses for he is busily creating a new set of commandments, which he calls “shared global rules”.

“Markets need morals,” he intoned. These, then, will be among the G20 Commandments: thou shalt not use tax havens, thou shalt not reward failure, thou shalt reshape the global financial system. (The tablet-chisellers will be busy, for Mr Brown will never stop at ten.) At the core of the “new global ethic” are the values of the family and the politics of the “kitchen table summit”. It is very old-fashioned, more Waltons than Simpsons.

Moral, moral, moral. It was the most used word in the speech. He talked of religions – Christians, Jews, Muslims, Buddhists, Sikhs and Hindus all got name checks – but in a moral sense. “We all feel the same deep sense that each of us is our brother and sister’s keeper.”

Now Mr Brown could not resist name-checking his own heroes. “Call it, as Adam Smith did, the moral sentiment, as Lincoln did the better angels of our nature, as Winstanley did the light in man. Call it duty or simply conscience – it means we cannot and will not pass by on the other side when people are suffering.”

The speech was almost a half hour. I fear the angels nodded off at one point but Gordon, looking out on an audience of 2,000 including two Grand Muftis, did a Bill Clinton. It was Mr Clinton who gave us “ubuntu”, an African word that means “I am because you are”. Now Mr Brown explained how economists once told the poor they must follow the free market because of Tina (There Is No Alternative). But campaigners fought Tina with Themba: There Must Be An Alternative.

“In that cry – Themba! – we hear everything that must guide us today,” he said, adding that the acronym was also a Zulu word for the most important thing humans could have. “Hope!” he cried in a rather unPresbyterian way. “Themba – the confidence, conviction, and certainty that where there are problems there are always solutions.”

So there you have it, a new quasi-religion, called Themba, in which people around a kitchen table tell bankers not to be so greedy. Add a few limos, photo calls and up to £50 million for lots of bumf on how not to be greedy, and it sounds like the G20 to me.

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