In March 2003 the US and UK decided to invade Iraq and topple Saddam Hussein. Much has happened since, most notably the wave of Arab spring revolutions that might eventually have cast him from power without intervention. But 10 years on, the US, Britain and the Middle East still live in the shadow of that fateful decision.

Two questions dominate. Was the invasion justified? And what have we learnt from it? The answer to the first is a resounding no. Saddam was a tyrant whose record in Kuwait and against the Kurds rightly worried the west. But the Bush administration’s attempt after 9/11 to link him with Osama bin Laden as part of some crude Muslim challenge to America was wrong.

The US and UK grossly exaggerated Iraq’s weapons of mass destruction. War was waged on the premise that the west could bring instant democracy to the country. Above all, it embroiled the US and UK in an eight-year conflict that distracted attention from securing Afghanistan, which delayed and ultimately undermined progress there. The invasion was arguably the biggest diplomatic error of the post-second world war period.