Britain just joined Saudi Arabia's war and America is still refusing to

Britain just sent its own military into the Yemen war.

One RAF plane. A single job. Refuel Saudi jets in the air.

Andy Burnham, the Prime Minister, announced it on his flight to the UN General Assembly in New York, about a day ago. Saudi Arabia asked for help. He said yes.

Andy Burnham says quote "on the advice of the defence secretary and the foreign secretary, I agreed to that request for defensive air-to-air refuelling".

He agreed after advice from Wes Streeting, the Defence Secretary, and Ed Miliband, the Foreign Secretary.

So what's actually flying? One RAF Voyager. That's a tanker plane. It refuels other jets while they're in the air, so they can stay up longer.

It's flying out of RAF Akrotiri, Britain's base in Cyprus.

And Britain has drawn a line. This plane only refuels Saudi jets defending against Houthi drones and missiles. Not jets flying strikes on the Houthis.

So Britain is trying to help Saudi Arabia defend itself, without joining Saudi Arabia's attacks.

Burnham calls it time-limited. He says it stays under review. Officials expect a matter of weeks, not longer.

Small mission. Short mission. Boxed in on paper.

But here's the thing. RAF fuel is now going into Saudi jets flying combat missions. Defensive or not.

So how did we get here? Saudi Arabia has two main ways to export its oil. The Strait of Hormuz. The Bab al-Mandeb strait. Iran and the Houthis have disrupted both.

About 12% of all world trade normally passes through Bab al-Mandeb. Saudi Arabia has had to reroute its oil through Egypt's Suez Canal instead.

And the Houthis keep advancing. In recent weeks they've taken the port city of Mocha and several Red Sea islands. Right now, fighting is happening in the Kahboub Mountains, on the border of Taiz and Lahj provinces, as Houthi and government-aligned forces fight for the high ground.