James Dornan, the MSP for Glasgow Cathcart, clarified that his prediction that Conservative MP Ross Thomson would end up as the 'fag' of potential Prime Minister Boris Johnson was a reference to a 'public school term'.
In a Twitter discussion about whether the Conservative leadership front runner Mr Johnson would scrap the Scottish Parliament, Mr Dornan wrote: "He’ll be too busy quaffing champagne and telling his new fag, my money is on Ross Thomson for that position, to keep still whilst he uses his back as a table. Honestly I don’t think he cares about Scotland at all."
Mr Thomson, who is gay, is regarded as one of the staunchest allies of the former Foreign Secretary, although he is yet to declare who he will back in the upcoming race to replace Theresa May as Conservative leader and Prime Minister.
Mr Dornan was immediately challenged for his use of the term 'fag', which the Cambridge dictionary defines as a offensive slur for a gay man, though it notes the phrase has an 'old fashioned' use as a term for a young boy at an English private school.
A pro independence tweeter wrote to Mr Dornan: "Hi James, as a "fag" who voted for you in 2016 would you care to explain what the hell this tweet is about?"
The former Glasgow City Councillor wrote back: "I honestly never thought for a second about that use of the word, never used it and never consider it. As explained by James McKenzie it’s about the public school practice. My apologies if anyone was upset by it, I’m horrified."
Katie Frank, Mr Thomson's 'Head of Office' in his Aberdeen South constituency, tweeted: "Using homophobic comments is not okay. Politicians in the LGBT community get enough abuse as it is. Saying you have gay friends and family does not excuse using this language The @theSNP must condemn this behaviour now. No excuses."
Mr Dornan later added: "It makes perfect sense if a) you know Boris did go to public school b) ‘fagging’ is a well established, if ridiculous, practice and c) you’ve ever seen Ross fawn over Boris. I’ve already apologised for any misunderstanding of the use of the word. Not sure what else can be said."
A Scottish Conservative party spokesman told the Herald: “Unfortunately, James Dornan has form when it comes to making crass and offensive remarks.
“Frankly, this is unbecoming of a member of the Scottish Parliament.”