Details have emerged of the first conversation between US President-elect Donald Trump and Theresa May, the British Prime Minister.

In an exchange that astounded some political observers in the UK, Mr Trump told Mrs May: "If you travel to the US, you should let me know," seemingly oblivious to the months of preparation that go into an official visit, not to mention the usual diplomatic protocols.

The details emerged after a transcript of the call was leaked to the Times newspaper in the UK.

The Times reported that the "informality of the invitation raised eyebrows among British officials", while The Independent said Mr Trump's "extraordinarily casual phrase" was said to have "stunned civil servants".