Britain is facing a diplomatic crisis with the US over Donald Trump’s plans to forge an alliance with Vladimir Putin and bolster the Syrian regime.

In a significant foreign policy split, officials admitted that Britain will have some “very difficult” conversations with the President-elect in coming months over his approach to Russia.

It comes after Mr Trump used his first interviews since winning the US election to indicate that he will withdraw support for rebels in Syria and thank Vladimir Putin for sending him a “beautiful” letter.

Mr Trump said that he will instead join forces with Russia and focus on defeating Isil. He has previously said it would be “nice” if the US and Russia could work together to “knock the hell out of Isil”.