It was announced on Monday afternoon that the Commonwealth Games gold medallist would be entering the political arena for the pro-independence party as a Lothian Region list candidate.
But since then, a number of “offensive” tweets have emerged resulting in accusations of homophobia and bigotry.
One such tweet from the 42-year-old that is now facing criticism is from January, 2020. It read: "Them Romanian beggars in Edinburgh ain't hungry!! Just drove past them all ready to switch up begging posts and ALL em fat as big juicy over fed pigs."
More recently, on February, 26, 2021, he appeared to question the use of vaccines, he said: “I’d rather not take an injection for something my perfectly good immune system can fight of quite easily. I was happy my parents & grandparents got it.
"I just don’t believe I need it."
Other Twitter users also highlighted that Mr Arthur would need to “be more careful” about other content he engages with on the site, as one tweet he was seen to have “liked” read: “**** Gypsies”.
On Monday night, in response to the “unintentionally offensive” tweets, Edinburgh-born Arthur took to twitter to offer an explanation and apology for his words.
His statement said: “I am a working class boxer who shoots from the hip. I don’t have spin doctors. But I want to clarify some points, and apologise for any offence that could have been avoided if I’d thought more about my words.”
The apology went on to say that he had been informed that the vaccine did not stop transmission of the coronavirus and as a “young and healthy man” he was not in any of the at risk groups. Since he said has learned that the vaccine is the “way we will get out of this pandemic”.
It continued: “Any comments about beggars that now look inappropriate are being misinterpreted, but that is my fault for the wording.
"I am not in any way racist as anyone who knows me will confirm…
"I apologise for any unintended offence, but I do not want it to distract from my central cause which is all of the people who live in Scotland.”