Alex Salmond thinks that Donald Trump will pose a real threat to the US if elected Picture: John Devlin

The former first minister of Scotland has claimed the Republican presidential candidate is emotionally akin to Peter Pan and can swing from “bonhomie to bullying” in a single phone call.

Mr Salmond had a much-publicised falling-out with the billionaire businessman when the latter sought to block a wind farm development near his Aberdeenshire golf course.

Now, as race for the White House tightens in the polls, Mr Salmond has written about his own encounters with the controversial would-be president.

Sign up to our daily newsletter The i newsletter cut through the noise Sign up Thanks for signing up! Sorry, there seem to be some issues. Please try again later. Submitting...

In an article for the Daily Record newspaper, he wrote: “Trump swings from public support to extreme opposition with no intervening period whatsoever.

“Indeed, in the course of a single phone call, he would veer alarmingly from bonhomie, to bullying, to pleading and then back to a jocular mood. Emotionally he is a Peter Pan - the boy who never grew up.

“This disagreement between us was just about wind turbines! Imagine the consequences if similar phone calls were taking place from the Oval Office, not Trump Tower, and the subject matter was not wind power but hard power - military force and nuclear weaponry.”

Recounting a Democrat campaign advert from 1964, when the party sought to highlight what it saw as the dangers of Republican presidency with nuclear strike countdown, Mr Salmond added: “As this campaign reaches its climax, they should consider using such an approach again.

“Because while many disgruntled Americans are still attracted to Trump’s anti-establishment, anti-Washington, anti-big government rhetoric, only a few want to risk a manchild in the White House.”