* UEFA will back Prince Ali to succeed Blatter
* Platini suggests UEFA could quit FIFA
* Platini has "tears in eyes" as he tells Blatter to go
By Brian Homewood
ZURICH, May 28 (Reuters) - UEFA president Michel Platini delivered one of his most emotional and animated performances since his playing days when he said it was time for Sepp Blatter to quit as president of FIFA with world soccer's body facing yet another corruption crisis.
He said that he hoped that 45 or 46 of Europe's eligible 53 voting nations would vote for Jordan's Prince Ali Bin Al Hussein in Friday's presidential election against Blatter who is standing for a fifth term as president.
Those votes would not be enough to topple Blatter but would send a strong signal of disapproval.
Platini suggested UEFA could withdraw from FIFA if huge changes are not brought in to world soccer's embattled governing body, but also admitted he faces something of a crisis of his own.
David Gill of England, who is joining the FIFA executive committee as the British vice-president, has said he will not take up his seat on the executive if Blatter is re-elected. Platini said he hoped he could persuade Gill to change his mind over the next few weeks.
Platini, one of the greatest footballers of all time, said he began his long relationship with Blatter in 1998 by which time he had swapped his France shirt to become the organiser of the 1998 World Cup in France.
"I have affection for Mr Blatter, and he always said he was like an uncle to me. But enough is enough.
"If I cannot tell him it is time to stop then who can? A true friend can tell another friend the reality."
Platini said that during an emergency committee meeting at FIFA earlier on Thursday, he told Blatter to step down.
"I said, I'm asking you to leave, FIFA's image is terrible. He said that he couldn't leave all of a sudden."
Platini added: "I'm saying this with sadness and tears in my eyes, but there have been too many scandals, FIFA doesn't deserve to be treated this way."
Platini, who decided last August to stand for re-election as UEFA president and not run for the FIFA presidency, originally was a close ally of Blatter, but was fulsome in his support of Prince Ali, who is the only candidate facing Blatter in Friday's vote.
"Prince Ali has all the legitimacy he needs, he is young, he is ambitious and that is why I support him, he can do some good, he can change things, he doesn't need money because he is a Prince," Platini told reporters at a news conference.
"A very large majority of national associations from Europe will vote for Prince Ali, and if they are to be trusted I believe he will get 45 or 46 votes from Europe. I'm trying to convince a couple who are not convinced."
FIFA's 209 members will vote on Friday with a two-thirds majority needed to win on the first ballot. If that does not happen then a straight majority is required to win a second ballot.
Asked if he realistically believed that Blatter could lose Friday's vote, Platini replied: "I think he can be beaten, yes. Before yesterday no, but after what happened yesterday, yes. Enough is enough. I think there will be a lot of changes."
On Wednesday police officers arrested seven FIFA officials in Zurich on corruption charges while authorities in the United States issued proceedings against 18 others involved in alleged corruption involving FIFA matters.
"I am the first one to be disgusted by this (FIFA corruption). I have stomach trouble when I think about the FIFA problem," he said."
"I am a great admirer of FIFA and I've followed it for some years, but I don't know where to put myself. I get the impression that if FIFA is not going to do anything, the FBI will do it for them."
Platini added that UEFA's members would consider its future position with FIFA on June 6 at the Champions League final in Berlin, one week after the dust had settled.
He said that he "did not wish" a European boycott of the World Cup, but added that preserving Europe's current total of 13 places at the 32-team tournament was a "red line not to be crossed."
"President Blatter is playing with the World Cup slots, so everyone is nervous. I have an iron-clad mandate from all European associations and there is a red line that will not be crossed and that is our number of slots in the World Cup."
"Europe will not lose a slot in 2018 and then in the World Cup in 2022, we will stick to 13. That will not be changed, we are not going to allow that."
Writing by Mike Collett; Editing by Giles Elgood