The US ambassador to the United Nations, John Bolton, has told British MPs that military action could bring Iran's nuclear programme to a halt if all diplomatic efforts fail. The warning came ahead of a meeting today of the International Atomic Energy Agency (IAEA) which will forward a report on Iran's nuclear activities to the UN security council.

The council will have to decide whether to impose sanctions, an issue that could split the international community as policy towards Iraq did before the invasion.

Yesterday the US secretary of state, Condoleezza Rice, said: "Nobody has said that we have to rush immediately to sanctions of some kind."

However the parliamentary foreign affairs committee, visiting Washington last week, encountered sharply different views within the Bush administration. The most hawkish came from Mr Bolton. According to Eric Illsley, a Labour committee member, the envoy told the MPs: "They must know everything is on the table and they must understand what that means. We can hit different points along the line. You only have to take out one part of their nuclear operation to take the whole thing down."

Let's say, for the sake of argument, that the international community (as represented by the United Nations Security Council) decides that Iran is in violation of its anti-proliferation commitments. And let's say that they conclude that something must be done to prevent Iran from going forward with an effort to produce a nuclear weapon. Do we want to tell them what we perceive our options to be? And if we do not have any consensus for tactical strikes, do we want to make threats of this kind? And even if the answer is 'yes', is the United State ambassador to the United Nations the right person to be rattling America's sabre?

Once again, we are facing a situation where the administration is divided. The CIA appears to be the most opposed to bombing Iran. The State Department seems to agree. But:

The Pentagon position was described, by the committee chairman, Mike Gapes, as throwing a demand for a militarily enforced embargo into the security council "like a hand grenade - and see what happens".

We lobbed our armed forces into Mesopotamia, and we can all see what happened. And this time, we won't have the Brits at our back.