Even before G8 planners started adding first five, then a dozen, and now double that number of governments to the guest list, the shrunken time frames and swollen agendas of G8 summits had long ceased to offer much scope for deep thinking — indeed, any thinking at all.

Carefully choreographed formal proceedings traditionally oblige each leader to zip through the “to do” list — how to save the global economy, save free trade, save the planet, feed it; and, finally, ah yes, though we’re not sure how, how to stop North Korea and Iran going nuclear.

In the expanded G8+ sessions there is no way to buck convention but in the session on foreign policy with which they kick off today, eight powerful politicians should break with tradition and do some real thinking. Binning their prepared remarks, they should concentrate, with what Barack Obama loves to call “the fierce urgency of now”, on a single question.

That question is how to exert pressure on Iran’s Islamic dictatorship, now that the political landscape has been transformed by the Khamenei-Ahmadinejad electoral coup and above all by the Iranians’ refusal to take it lying down. What is happening is no “mere” popular burst of indignation, brutally suppressed. The upheaval reaches deep into the heart of the regime, pitting factions of the clerical and political establishment fiercely against each other and even calling into question the moral authority of the Supreme Guide, the keystone of rule under divine guidance.

In open defiance of Ayatollah Khamenei’s order to unite under Mahmoud Ahmadinejad, groups of Iran’s most revered mullahs have denounced the new Government as “illegitimate”, and two thirds of the members of the Majlis, Iranian’s parliament, boycotted the President’s “victory” party. In the fight between two Irans, one obscurantist and belligerent, the other increasingly sophisticated, youthful and weary of isolation, Ayatollah Khamenei was never neutral. With his fateful decision to step off his pedestal and demand that heads be cracked, he can no longer even pretend to be so. A taboo has been broken.

The international interest in an Iran that behaves like a “normal” country thus coincides with Iran’s anguished national mood. Whether Mr Obama’s offer of unconditional talks with the regime ever made sense is open to question — all he got in exchange were demands that America “repent”, drop sanctions and dissociate itself from Israel. To keep that “pathway” open now would be anything but a neutral act: it would confer legitimacy on a regime that has forfeited Iranian trust, demoralise Iran’s opposition and confirm hardliners in their conviction that the Obama Administration is in retreat.

Further, and much to the point, to talk about talks now is just talk: negotiations, even were Iran to take up the offer, would not achieve the goals of ending Iran’s lethal mischief-making in Lebanon, Iraq, Palestine and Afghanistan, still less its pursuit of nuclear weapons.

Carrots do not work with either Ayatollah Khamenei, or with Mr Ahmadinejad, who since stealing the election has declared the nuclear programme non-negotiable. What then? The sticks of economic sanctions are notoriously difficult to aim against elites without hurting people who, in Iran’s case, are already hard hit by unemployment, inflation, rank inequality and mismanagement. They also take time to work, and time, on the nuclear front, is short.

But increased economic pressure now would chime with the accusations, levelled at Mr Ahmadinejad by his main challenger, Mir Hossein Mousavi, that mismanagement and “adventurism” have led to economic misery and international disrepute. Since Iran depends on Europe for 40 per cent of its imports, mainly from Germany, Italy and France, a sharp temporary trade freeze would be devastating — particularly if it included petrol, which Iran imports for lack of refining capacity. Sanctions would hit the wealth of Revolutionary Guard commanders, who control vast tracts of the economy. They would also reveal Mr Ahmadinejad’s North Korean-style “self-sufficiency” rhetoric for the economic rubbish it is.

The Europeans, however, will not move unless they can be convinced that sanctions form part of a coherent Obama strategy. The L’Aquila summit needs at the least to convince them that the US is getting its ducks in a row.

Public diplomacy towards Iran also needs drastic overhaul. A basic Western misunderstanding has been that, 30 years after Khomeini’s revolution, Iranians are still brainwashed by his aggressively messianic message. This misconception underpinned the West’s pathetic eagerness to be seen not to “intervene” in Iran’s drama, a sacrifice of principle for no reward since the regime blamed satanic meddling anyway. Even at the height of Khomeinist fervour, the massed black-clad rallies were far from the whole story — some five million Iranians have spent time in jail since 1979 — and experience has inoculated most Iranians against permanent Islamic revolution.

Their courage has more than earned Iranians the right to be treated as adults. At least a third are plugged into the information revolution by satellite and mobiles. And they are in a mood to listen. They have been told that their nuclear programme is peaceable, and it is as such that it has massive support. Detailed evidence that the regime has lied to them is worth laying out, clearly and repeatedly, together with an explanation of the links between non-compliance and sanctions, and the rewards on offer for Iranian co-operation.

The Big Lie about the elections haunts every corner of Iranian life, colouring everything the regime now does. Pussyfooting by the West has never been more inexcusable, or truth-telling more likely to find a receptive Iranian audience.

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