Free Church of Scotland minister David Robertson has said that politicians rejecting Donald Trump are simply using "cheap and easy virtue signalling" to appeal to their base.

Speaking on BBC Scotland's Debate Night, Mr Robertson admitted to finding the US President "not remotely Christian" but said that if politicians wanted to snub him then they should "be consistent" and do the same to the leaders of countries like China, which has imprisoned Muslims and demolished churches. 

"He may be Presbyterian, he may be Protestant or whatever you want to call it [but he is] not remotely Christian," said Mr Robertson. 

"And I would say that unequivocally.  I find him to be a boorish, rude, arrogant man.

"However, and I will say this, [...] I have no doubt at all that the University of Strathclyde, that the Scottish Government and others would accept money from the Chinese Government for research and elsewhere. 

"Donald Trump has not locked away or put into concentration camps two million Muslims as the Chinese have. 

"My last information was that there are over a thousand churches that have been torn down in the past 18 months. 

"Yet we honour the Chinese Government, we would take the money from the Chinese Government, so if politicians are going to talk about values and go against Donald Trump, I regard it as cheap and easy virtue signalling to their base rather than dealing with the reality, unless they are prepared to be consistent." 

Mr Trump is on a three-day state visit to the UK.  On Monday, he was welcomed by the Queen at Buckingham Palace and had a state banquet held in his honour. 

The banquet was boycotted by Labour leader Jeremy Corbyn.

Mr Trump was also given a tour of Westminster Abbey, where he laid a wreath in honour of fallen soldiers from the two World Wars and subsequent conflicts at the grave of the Unknown Warrior. 

Before even touching down, he had already sparked a row with London Mayor Sadiq Khan after calling him a "stone cold loser" on Twitter. 

Mr Robertson expanded on his Debate Night comments on his blog, The Wee Flea, saying that it was "double standards" if a politician protests Trump's visit over misogynistic or anti-Muslim views "but welcomes with open arms a government that forces women to have abortions and imprisons Muslims". 

"It is a classic example of the double standards of the progressives – whose 'values' seem to ebb and flow according to what they are dealing with," he said.

"My problem is not with Strathclyde receiving money – in the world of real politik that may be the best thing to do (that's another debate) – it's the double standards I don't like. Real politik for some – purity for others," he said. 

He added that while he respected Trump as US President, it was wrong for Christians to view him as an "ambassador for Christ". 

"I respect the office of the President and think that as President he should be welcomed and honoured here. And I think that God can use him (as he could use Clinton, Obama or Bush)," he said.

"But I will not allow the Gospel and the future of the Church to be tied to a man who shows no understanding of the Gospel and no fruit of the Spirit. Trump may be your President – but he is not my brother in Christ, nor my Saviour. And I object strongly to President Trump being viewed as an ambassador for Christ. He isn't."