Israel has just handed Iran a major victory

What is the point of retaliation? Not revenge, for that is no way to conduct serious foreign policy. Not domestic politics, for drumming up popular support is not a reason to send a nation’s sons into action. No, the point is security. The point is to create a deterrent.

By this measure, did the Israeli strike on Isfahan achieve its objective? It is too early to tell, but the first indications are that if no further action is to follow, it was unlikely to do so.

If there is one adjective that has been attached to the assumed Israeli retaliation in recent days, it is “limited”. It has been used by the Americans, it has been used by the Israelis, and it was used by the British diplomats I spoke to who returned from Israel on Thursday. “Limited” is all very well; it plays nicely to the international community who are congenitally bent on holding Israel to a draw. But it will hardly strike fear into the heart of the Iranian regime.

What actually happened? At the time of writing, explosions were heard early on Friday morning near Isfahan in central Iran. The city is home to a variety of military targets, including the subterranean Natanz nuclear site, which has been targeted repeatedly by the Mossad. It also hosts an air base, which is thought to have been the target of the strikes.

The attack is thought to have been carried out by drones rather than missiles or airstrikes, perhaps launched from within Iran itself. Jerusalem has not yet taken responsibility for the operation, providing deniability with an inbuilt exit from the spiral of escalation.

The full details are yet to come out. But was that really it? Was that really the only response to hundreds of missiles and drones fired at Israel last week, costing a reported $1 billion (£804 million) in defences and demanding an international response? If the price for such a major assault is one “limited” jab at an air base, then that is extremely favourable to Iran. The lesson for the Ayatollah is clear: next time, double the payload. It’s worth it.

After years of American appeasement, Tehran has learned that its adversary sees deterrence as an alien concept. The White House is quite happy to work around its own sanctions legislation to release pots of cash to the regime. It is quite happy to engage in interminable nuclear talks while failing to halt Tehran’s progress towards a bomb. It is quite happy to play defence, even having the temerity to call it a “win”. But when it comes to hitting back, it is cowardly.

Make no mistake: this was not the preferred Israeli response. It was heavily muted by international pressure, particularly by the Americans. After last week’s show of solidarity, how could Israel refuse? Again, we must remember that more details may emerge; more attacks may come. But if they don’t, then it is hard to resist the conclusion that after coming so gallantly to the defence of the Jewish state, America, Britain and other allies have used their diplomatic power to advance the interests of Tehran.

Iran’s foreign policy has always been based on a principle of increments. As in a game of grandmother’s footsteps, it inches the boundary forwards little by little, seeking the biting point that signals it has gone too far. Then it pauses for a while before pushing forward again.

In a normal scenario, however, grandmother – who is, after all, far more powerful – suddenly turns round and scares the children away. It seems that the West has forgotten how to play the game.