According to the Arab press, Mahmoud Ahmadinejad is planning to end his tour of Lebanon by symbolically lobbing a rock at Israel over the border fence.

The thinking, presumably, is that this would be a great PR coup - that the image would cement Mr Ahmadinejad's reputation as the Islamic world's foremost opponent of the Jewish state. But would it really?

The move (if it ever happens ) would, of course, be modelled on the famous photo of Prof Edward Said, who in 2000 threw his own stone at Israel. It is worth remembering that Professor Said's photo, which was reproduced around the world, did him enormous damage in the West, making him look like a hot-headed agitator rather than a reasonable, respectable academic.

Mr Ahmadinejad has very little credibility in the West to ruin, but many people would find an image of him personally engaging in political violence distasteful.

In his own country, Mr Ahmadinejad has often been criticised for being too focused on the Palestinian issue at the expense of his own people, and also for projecting an image of Iran that is mad, dangerous and outside the community of nations. A picture re-enforcing those exact perceptions might not be too popular at home either.

Naturally, we would all prefer not to see Iran's dictator getting the satisfaction of throwing rocks at Israel. But given that there is very little Israel can actually do to stop him, I say, rock on, Ahmadinejad. Give us the picture that will instantly convey, to any remaining doubters, just how mad you really are.