British combat operations in Iraq came to a formal end today. “Iraq is a success story”, proclaimed Gordon Brown, our prime minister.

But is it? There is an ominous increase in terrorism in Baghdad. I was shocked to read in this morning’s paper that three car bombs had gone off in Baghdad, killing 41 people (the death toll is now over 50). This was shocking both because of the news itself, and because it merited no more than a “news in brief”. That reminded me of the dark days when violence in Iraq was so widespread that it barely merited comment. Are we getting back to that? Earlier this week, there was another spate of car bombings that killed over 80 people.

So what is going wrong? The casual observer might blame all this on Obama’s plan for a withdrawal of US troops. But the pull-outs have barely started. A more plausible explanation might be that, as part of its handover of responsibilites to the Iraq government, the US has stopped paying the Sunni paramilitaries whose support was so critical to suppressing the activities of al-Qaeda in Iraq.

The Brits and Americans are still emphasising the huge improvement in the security situation over the past two years. But the current spate of violence threatens to vindicate those who always warned that “the surge” had not solved the Iraq problem, and that communal tensions and violence were bound to re-emerge.