You might say, in Britain or America, that this amounts to progress. The Security Council has moved fairly fast — in weeks, not months, that is — to produce a combined statement.

Even though it is signed by just the permanent five, plus Germany, it begins to put a “UN” label on the demand. That is surely the best way to convince Iranians that this is not a campaign by the “Great” and “Small” Satans. But the gaps in it are so big that they advertise the group’s weaknesses.

First, the statement is not legally binding. Secondly, Russia and China insisted very publicly on the deletion of a clause referring to the Security Council’s role in maintaining international peace and security. They argued that this too closely resembled the UN charter’s Chapter VII, under which the council can authorise sanctions or military action.

By doing this, they made clear the strength of their opposition to sanctions, let alone force. Despite the declaration yesterday by Condoleezza Rice, the US Secretary of State, that “the international community is united”, it is not.

The reasons why Russia and China are so loath to contemplate sanctions against Iran are clear. Russia is in the middle of selling Iran equipment for its legal civilian nuclear programme. China has signed deals to buy oil and gas from Iran to fulfil its energy demands in the next decade.

Any debate about economic sanctions would surely start with a ban on selling nuclear kit, and then move to the oil industry — the two fronts that would hurt Russia and China.

In that light, Straw’s threat seems empty. He said that the council might pass a legally binding resolution if Iran did not give way within 30 days, and might move to “measures” after that. Asked whether that step might include sanctions, he replied, “It could do”.

It would not be surprising if Iran ignored that threat and chose to see instead that Russia and China have given it elbow room by their lukewarm support for the council’s action.

If the 30 days pass without movement from Tehran, the council may have to turn to non-economic sanctions, such as banning Iran from the World Cup. In a football-crazy country, that would certainly communicate the world’s distrust, perhaps more than measures so far have done. But it would still be a long way from the threats that Straw was making. Without Russia’s and China’s support, they mean nothing.