Donald Trump brands First Minister ‘Mad Alex’ in wind farm row

But the Apprentice star was branded a “bully” and accused of being “hysterical” over the bizarre outburst, which marks the latest twist in the saga of his plans to build a golf course near Aberdeen.

Mr Trump is fighting proposals for an offshore windfarm which he argues will spoil his luxury coastal development.

He is to be the star witness at Holyrood committee inquiry into the Scottish Government’s renewable energy targets.

In the latest letter to the First Minister, Mr Trump said the drive to build wind turbines would ruin the environment and end any chance of Scotland becoming independent.

He asks: “Do you want to be known for centuries to come as ‘Mad Alex – the man who destroyed Scotland?’

“Remember what I said – if you pursue this craziness, Scotland will go broke and forever lose whatever chance you currently have of making Scotland independent.

“A bankrupt Scotland will always be reliant on others.”

But Mr Trump’s comments came under fire from unlikely defenders of the First Minister.

“I don’t normally rally to the defence of Alex Salmond,” said Liberal Democrat leader Willie Rennie. “But when old friends turn nasty with irrational taunts, I feel the need to step in.

“Climate change denier Donald Trump is turning more eccentric and hysterical by the day. He can’t bully Scotland against meeting its renewable energy ambitions.”

A planning application for an 11-turbine wind farm off Aberdeen Bay was submitted to Marine Scotland last summer and a decision is expected to be made later this year. Mr Trump has halted work on his resort near Balmedie, north of Aberdeen, until the decision is made by the Scottish Government.

• In pictures: The Aberdeenshire wind farm

His latest letter to the First Minister adds: “Be smart and try to get yourself out of this mess.

“History has shown that the world’s greatest leaders were the ones that were able to change their minds through knowledge. Be one of them!”

The Scottish Government said it had a “responsibility to ensure that Scotland seizes the opportunity to create tens of thousands of new jobs” through green energy developments.

A spokesman said: “We welcome the widest possible debate on how developing our clean, green energy resources is bringing industry and jobs to communities across Scotland.”

Mr Trump recently claimed he felt “betrayed” by Mr Salmond over the windfarm proposal.

Last month, he accused the First Minister of being “hell-bent on destroying Scotland’s coastline and therefore Scotland itself”.