NOT long after Turkish President Recep Tayyip Erdogan came to power, a senior US diplomat, then serving in Ankara, wrote that Erdogan was not going to be “Washington’s man”. At the time, his report was dismissed at the State Department. It seemed unthinkable to the panjandrums in Foggy Bottom that Turkey, a key NATO ally whose military was largely armed with US equipment, would ever actually cease to be an ally, no matter what sound bites Erdogan might serve up for the media.

Yet this is what has happened. Turkey is buying S-400 surface-to-air missile systems from Moscow and the increasingly confrontational Erdogan has made it clear that they will be used against US warplanes if necessary. It is therefore hardly surprising that the US Congress has just blocked the delivery of F-35 fighter jets to Turkey, which was due to start this week. Part of the deal was that the Turks would be involved in a co-production program, which would in effect have given them access to much of the advanced technology used by Lockheed Martin to build the stealth fighter. Washington legislators are in no mood to allow the full implementation of this $10 billion agreement which would have involved 100 of the warplanes.

Ankara has however already paid $800 million up front and is threatening reprisals if the jets fail to be delivered. A foreign ministry spokesman warned the move by Congress was “against the spirit of our alliance with the US.”

In point of fact, it must be said that blocking the deal is very much in the spirit of current Turco-US relations, which have never been so bad. Interestingly, the Russians agreeing to supply the anti-aircraft missiles also pledged to allow some manufacture in Turkey and sweetened the deal with an extremely generous financial package.

The UK is also working on a Turkish co-production deal for the fifth generation TF-X fighter jet, which is the more important to London since, thanks to Brexit, it seems that Britain is likely to be locked out of a Franco-German project to build the Typhoon Eurofighter’s replacement. Yet the TF-X negotiations with the Turks have stalled because Rolls Royce, which will be supplying the engines, is concerned at passing over key intellectual property to Ankara. The British engine maker does not wish to jeopardize its lucrative business powering the world’s airliners and knows that if Washington were unhappy with the Turkish contract, any sanctions it imposed could cripple the company.

One key consideration for all warplane makers is that it is certain that even if the fifth generation warplanes have pilots, they will be the last to do so. The autonomous fighter aircraft and indeed robot bomber are already on the drawing boards and may supersede the new warcraft before they even take to the air.

Whatever this development, it is clear that Erdogan is not prepared to be sanctioned by the US. He is limbering up for a military assault on the Kurdish PKK in northern Iraq and is seeking Iranian support. That of itself will harden the view of the Trump White House. The big question now is how Moscow will seek to exploit Ankara’s shattered relations with their old American ally.