Don Robertson has taken charge of six Celtic games this season, and four for Hearts.

Who would be a referee in Scotland? In a league routinely dominated by Celtic and Rangers, every contentious decision comes with its own subplot of supposed bias and intrigue. Which referee has, allegedly, been pigeonholed as a Celtic man? And who supposedly has a track record of being sympathetic to Rangers?

"There's always been this narrative surrounding Scottish football and referees," BBC Sport football expert and former Celtic forward Chris Sutton said. "Whose side are the referees on? That's the way it's viewed among both fan bases. There’s always been conspiracy theories doing the rounds."

After Celtic's controversial win over Motherwell on Wednesday, match referee John Beaton and his family were put under police surveillance following a leak of their personal details online. "This is the inevitable consequence of the heightening criticism, intolerance and scapegoating demonstrated this season by media pundits, supporters, official supporters' groups, clubs, players, managers and former match officials," the Scottish FA said.

"Those who have sought to apportion blame and conspiracy towards match officials to deflect from defeats or perceived injustices throughout the season have contributed to an environment that puts the safety of our staff and match officials in jeopardy. The Scottish FA condemns in the strongest possible terms attempts to compromise the safety of match officials."

On Saturday, Celtic meet Hearts in a first-in-a-generation final game of the season to determine the Scottish Premiership champions. It will be once again incredibly high stakes and, for the officials, extreme pressure.

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The rumour and speculation of supporters was tested to its limits on Wednesday when Celtic were given a hugely controversial and crucial stoppage-time penalty at Motherwell, given after a video assistant referee (VAR) review. The VAR, Andrew Dallas, had sent referee Beaton to the pitchside monitor for handball against Sam Nicholson. Kelechi Iheanacho despatched the spot-kick, giving Celtic a 3-2 win and changing the complexion of the final day of the season. Any victory would now give Celtic the title. Without the VAR penalty at Fir Park, Martin O'Neill's men would have needed to win by at least three goals.

Hearts boss Derek McInnes called the penalty given to Celtic "disgusting", and has suggested they are not getting their fair share of decisions. "We're up against it, we're up against everybody," McInnes said.

In the aftermath, social media was full of doctored images trying to prove either that the referee had got the decision wrong or made a mistake. Later, Hearts' owner The Foundation of Hearts issued a statement, saying that it was "extremely concerned by a number of refereeing and VAR decisions" in recent weeks. It added that it was calling on "those responsible for the officiating of Saturday's match to ensure that the highest standards of decision-making are applied".

Then, on Friday afternoon, the Scottish FA's revealed Beaton and his family had needed police protection. "This is the consequence of a hysterical media narrative, fuelled by irresponsible knee-jerk post-match media interviews, commentary and official social media posts," the SFA said. "Referees are not infallible. Mistakes will be made on the field, and subjective calls made in front of the VAR monitor, just as managers will pick the wrong team, goalkeepers concede soft goals and strikers miss from five yards out. Yet the reaction to these inevitabilities could not be more contrasting."

"What happened yesterday is not an isolated incident. There are many examples of match officials being placed in harmful situations but with individuals fearful of speaking out lest it exacerbates the situation or causes further alarm to friends, family and colleagues. We will not allow this to become the norm. We will not allow a situation where match officials require special provision to protect their children at school to be considered an occupational hazard. We will not allow a situation where staying at home with the front door locked and avoiding the hazards of public interaction becomes a coping strategy."

Sutton said he appreciates where McInnes is coming from, but that the reaction to Wednesday's VAR decision came with its own unconscious bias. "I think there's so much hysteria because people are so desperate for Hearts to win the league because of the story," Sutton added. "I can understand McInnes' frustration, and I can understand what he's doing. He is trying to create a siege mentality. There's no doubt there is a sort of psychological pressure trying to be exerted on the referees ahead of the game."

Celtic supporters had long since dubbed the referee 'Brother Beaton', insinuating he has been favourable to Rangers. Dallas, meanwhile, is the son of former professional referee Hugh. His father was once struck by a coin thrown by a home fan in the Old Firm derby at Celtic Park. That, according to the online conspiracies, means Andrew must have dislike for the green and white.

On Saturday's game, the referee is Don Robertson and VAR Kevin Clancy. Robertson was the referee for Hearts' 2-1 win in the Edinburgh derby on 26 April, showing red cards to two Hibernian players. Might he be seen as more on the side of the Jambos? But the VAR, if you ask Rangers fans, is more likely to favour Celtic - some supporters refer to him as 'Father' Clancy.

Referees, of course, do not have any such allegiances, and go out to officiate each game impartially. "I'm sure they're thinking about the implications," Sutton said. "But if they get a controversial moment, they can only go out and do the job to the best of their ability."

Kevin Clancy will be at Clydesdale House to take charge of the video reviews for the title decider.

Former referee Bobby Madden told BBC Sport that Robertson and Clancy will need to thrive off the occasion. "Unfortunately in recent times there are too many key matches incidents that are going the wrong way for match officials which brings that added pressure," Madden said. "One of the challenges in Scottish football is they don't have a big enough refereeing pool at the moment. So it's the same referees who are undertaking the key matches. That in itself presents its own challenges and its own pressure. "You want to referee these games and hope nobody is talking about you."

Madden agreed with Sutton that this has always been in the way in Scotland, and probably always will be. "With every referee and every player - everyone involved in Scottish football - if someone answers that they support Motherwell they are asked 'who is your real team, or who is your big team?'. These kind of wild conspiracies have been in Scottish football for a long time and I don't think they'll ever go away. And I don't think this season has done anything to make that happen."

All eyes now turn to Parkhead on Saturday, one game to decide the destination of the title. Robertson and Clancy, and the rest of football, will be hoping they are not the story.

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