I’m too lazy to give this the write up it deserves, but here’s the hot wash. One of the most critical functions of an air force, any air force, is reconnaissance. And of the various types of recon, perhaps none is as critical as signals intelligence, or SIGINT.
And the crown jewels of airborne SIGINT is the USAF’s RC-135W Rivet Joint. Based on a heavily modified KC-135 airframe, the Rivet Joint sucks up just about every electron in the air.
Britain, long a pioneer in electronic wizardry in the sky, found its old Nimrod R1 program in shambles. After exploring various options, they settled on buying three new-build* RC-135Ws for themselves. And rather surprisingly, the US went along with this. It’s not publicly acknowledged, but I suspect there is an agreement in place for sharing the “take” from these platforms.
The first British Rivet Joint was delivered this spring and the RAF is still learning to operate it. One step recently was the first aerial refueling. Because all of Britain’s tankers are hose and drogue tankers, the Rivet Joint will have to rely on US tankers with the flying boom to support their missions.
*Actually, the airframes are all former KC-135R birds that first flew in 1964, but the point is, they’re being converted to Rivet Joint now, as opposed to taking delivery of existing US Rivet Joints.