Why did Israel attack Iran? And what does it mean for the rest of the world?

Israel has finally hit Iran's nuclear facilities.

What happens next and how bad could it get? Israel first. Israelis have always regarded Iran's nuclear ambitions as an existential threat.

Israel-Iran latest: Iran retaliates against airstrikes The ayatollahs insist their nuclear programme is entirely peaceful, but their leaders have also talked of wiping Israel off the face of the Earth, and that threat has been taken at face value by Israelis. Benjamin Netanyahu clearly thinks this is the time to act for a number of reasons.

Iran has never been weaker internally after nationwide protests a few years ago, and Israel has massively degraded its proxies, Hezbollah and Hamas. And they have a sympathetic president in the White House.

Israel may have plenty on its plate in Gaza and southern Lebanon still, but that is not holding its leaders back from seizing the moment. Critics might also wonder whether this is a distraction from the growing diplomatic isolation of Israel over Gaza.

Britain has just taken the unprecedented step of sanctioning two Israeli government ministers. France is thought to be poised to recognise Palestine as an independent state.

Whatever the reasons, Israel will try to finish what it's started. Equally, Iran will do what it can to stop Israel's attacks.

Doing nothing or not enough looks weak, and in the Middle East that is dangerous. But how? Missile and drone attacks on Israel seem certain, but possibly against US assets and allies too.

The Trump administration may have tried to distance itself from the Israeli operation. But Iran won't believe that.

For Iranians, America and Israel are inextricably linked as part of the same evil. Read more:Watch: Iran and Israel in major conflictIsrael attacks Iran and declares emergencyIran TV shows bomb damage The big fear is Iran starts striking targets in the Persian Gulf.

Enough tankers being sunk or oil refineries going up in smoke could have an immediate impact on the global economy. Bad enough and President Trump might call time on Israel's actions.

That would be the Iranian hope, at least. So expect the following: Israel continues striking Iran; Iran hits back with all it can; America is forced to help defend Israel; Iran hits both Israel, the US and possibly US allies.

That is the predictable bit. Wars follow the laws of unintended consequences.

At any point in that escalation, unexpected events could lead to greater escalation. Brace yourself, the coming days could go in a number of directions.

If the Persian Gulf becomes the battlefield, we will all feel the consequences..