Thaksin Shinawatra arrived at Manchester City in July to a fund of goodwill from success-starved fans - now he risks every shred of his sporting reputation by sacking Sven-Goran Eriksson.The mere mention of Eriksson's name is the catalyst for a variety of a emotions after his time of under-achievement and excess personal baggage with England.And yet the Swede now, rightly, finds himself the subject an outpouring of sympathy as Thaksin prepares to make his sacking official.Before outlining the scale of mistake Thaksin is about to make, it is only right to go back to June last year when I wrote a piece insisting the former Thai Prime Minister was wrong to appoint Eriksson.He was right. And I was wrong. Now he is very wrong.I questioned whether Eriksson was a modern team-builder and whether he had the hunger and desire to do the job at Eastlands. It was a view coloured by watching his listless performances at three major tournaments in charge of England.Eriksson has answered those charges emphatically in a first season that has been one of undoubted progression, despite a fade-out in the second half of the campaign.He has also achieved the specific goal set for him by Thaksin - namely a top ten Premier League finish.Eriksson had to work the transfer market quickly and effectively when he took over because he was barely left with enough players after the departure of Stuart Pearce and the clock was ticking on the new season.Martin Petrov and Elano brought class and creativity, while Croatia's Vedran Corluka was another success.He made mistakes, namely the £8m paid for striker Rolando Bianchi, but when a workable squad has to be assembled swiftly from the wreckage of what had greeted him, the odd gamble will fail.If Eriksson made a fatal error, it may have been by blending his new players so quickly and starting the season so spectacularly.This appeared to raise the expectations of Thaksin, a man who appears to have a slender grasp on the realities of football if he feels Eriksson's performance this season warrants the sack.As I have stated, there is a helping of humble pie with these words because I believed Eriksson would be a failure at Eastlands after the England experiences.But he had started to rebuild his own and Manchester City's reputation this season - and this should have only been the start.City have worked hard in recent years to cast aside a name for snatching defeat from the jaws of victory.This has been done behind the scenes and Eriksson was in the process of putting matters right on the pitch. Thaksin is now about to throw so much good work away.Eriksson has also shown a willingness to give City's exciting crop of young players their chance and it was clear they had faith in him.Word from City is that Eriksson is a hugely popular figure, revered and respected by everyone at the club - except, it seems, by the man who matters.If Thaksin thinks his sacking of Eriksson is the decisive hands-on action the club's supporters revel in, he is guilty of a desperately bad misjudgement.City's fans, almost unanimously, are outraged by the news and the cynics might even suggest it is rather handy for Thaksin that the axe is falling after City's final home game.This spares him inevitable protests at Eastlands, although City fans will make their voices heard in support of Eriksson at Anfield and The Riverside in the final two games of his reign.Thaksin is apparently lining up Portugal coach Luiz Felipe Scolari - and while the Brazilian is a World Cup winner with his own country, what is his knowledge of the Premier League?Eriksson's departure has reportedly devastated City's squad. What now for them? What of all the players Eriksson brought in?Make no mistake, the law of football dictes that predators will now be circling the likes of Richard Dunne, Micah Richards, Martin Petrov and Elano, ready to make capital of the uncertainty and unrest.Will the new man want Eriksson's signings? Will Thaksin effectively have to start spending again?What will the new man have to spend? When will he be able to spend it? And will he be allowed to spend it on the men he wants?And - crucially - will Thaksin start the sacking game again next term if City fail to achieve what appear to be his farcially unrealistic expectations?Eriksson achieved Thaksin's goal of a top ten finish with something to spare and will still be sacked. Would any manager of consequence be in a rush to join City with that backdrop?Manchester City is a club crying out for stability on the pitch after the wilderness years and Eriksson could have provided it.Sadly, Thaksin has chosen to demonstrate his impatience and sporting naivety in one fell swoop in a move that has alienated fans only too willing to give him a chance.Manchester City's fans do not deserve that. Manchester City as a club does not deserve that. Eriksson does not deserve that either.It remains to be seen whether this is the defining moment of Thaksin's reign - but he is in the process of committing a major error.