What is the price of success? If you’re a Manchester City fan with an interest in human rights, it’s a crisis of conscience. I’ve been here before. Eleven years ago my club was bought by former Thai prime minister Thaksin Shinawatra, who had presided over “very serious human rights violations” according to Amnesty. At the time, I wrote a sports column for the Guardian, and said that I could no longer reconcile my love for City with Shinawatra’s record so I was giving up on City.

Only football fandom is messier and more compromised than that. I soon discovered that I couldn’t give up on City just because my conscience told me I should. The club was in my blood. I’d backed myself into a corner, so I returned to City and gave up my column instead. Thankfully Thaksin was forced to sell City within a year because £800m of his assets were frozen in Thailand, and my inner voice screaming HYPOCRITICAL BASTARD was temporarily silenced.

This time round it’s even tougher. In 2008, Manchester City were bought by the United Arab Emirates’ Sheikh Mansour. The UAE is not a democracy, it is a federation of hereditary absolute monarchies. In other words, what the royals say goes – in every sphere of life. Sheikh Mansour is not only a member of the royal family of Abu Dhabi, he is deputy prime minister of the UAE, minister of presidential affairs and half brother of the president. Mansour has a lot of clout in the UAE.

In its 2017-18 report Amnesty condemned the UAE for unfair trials, lack of freedom of expression, a failure to investigate allegations of torture, discrimination against women and the abuse of migrant workers. City fans knew that the UAE had a dodgy human rights record. But many of us preferred to turn a blind eye. It was abstract – out of sight, out of mind. And there were endless positives. Mansour had invested billions in the club and the city; City were playing dream football – the first team to win 100 points in a Premier League season in 2017-18; we had the best manager in the world, and what’s more he cared – Pep Guardiola wore a yellow ribbon for political prisoners jailed after campaigning for Catalan independence. What was there not to love about City?

Well yesterday we found out, when British academic Matthew Hedges, who had been accused of spying, was given a five-minute trial without a lawyer, and sentenced to life in jail. UAE prosecutors said he had admitted to spying, though others claimed he is innocent. Jeremy Hunt, the foreign secretary, called it “totally unacceptable”, said there was “no evidence for the charges laid against him”, and warned of “serious diplomatic consequences” for the UAE, which Britain regards as an ally.

As for City, unsurprisingly not a word.

Just to reiterate, Sheikh Mansour is not just a wealthy individual in the United Arab Emirates: he and his family run the country and make all the important decisions. People live and die by their rulings. If I were as principled as I’d like to be, I’d denounce my club and walk away – of course, human rights trump a football club. But I tried that in 2007 – and failed. So for now, I’m sticking with City, while pleading with them to speak up for justice.

It is not good enough for the club to pretend this is not happening or it has nothing to do with them, and that if they ignore the fate of Matthew Hedges the issue will go away. It won’t – and the longer he is in the news, the more ethically bankrupt City will look– the glossy, globalised, media-friendly face of repressive government; launderer supreme of the politically unacceptable.

So what can Manchester City do? I beg City officials to state publicly that handing down a life sentence to a man without a fair trial is unacceptable, and that the club will do what it can to pressure the UAE to change its mind, and to address its wider human rights issues. Just as Sheikh Mansour has transformed City for the good, City now has the power to change the UAE for the good. Pep, over to you. I look forward to seeing you explain why you are now wearing your yellow ribbon for a different victim of state injustice.

• Simon Hattenstone is a features writer for the Guardian