Noel Gallagher has said he quit Oasis after becoming the victim of intolerable "violent and verbal intimidation".
The Mancunian multi-millionaire also blamed a "lack of support and understanding from my management and bandmates" as a reason for his abrupt departure.
Fans were left reeling after he announced he could not work with his brother Liam any more. Oasis are expected to decide in the next few days whether to continue without Noel.
In a statement on his blog at Oasisinet.com, Noel said: "The details are not important and of too great a number to list.
"But I feel you have the right to know that the level of verbal and violent intimidation towards me, my family, friends and comrades has become intolerable.
"And the lack of support and understanding from my management and band mates has left me with no other option than to get me cape and seek pastures new."
He went on to apologise for the band pulling out of a recent festival after Liam fell ill.
He added: "I would like firstly to offer my apologies to them kids in Paris who'd paid money and waited all day to see us only to be let down AGAIN by the band. Apologies are probably not enough, I know, but I'm afraid it's all I've got.
"While I'm on the subject, I'd like to say to the good people of V Festival that experienced the same thing. Again, I can only apologise - although I don't know why, it was nothing to do with me. I was match fit and ready to be brilliant. Alas, other people in the group weren't up to it.
"In closing I would like to thank all the Oasis fans, all over the world. The last 18 years have been truly, truly amazing (and I hate that word, but today is the one time I'll deem it appropriate). A dream come true. I take with me glorious memories."
He concluded: "Now, if you'll excuse me I have a family and a football team to indulge. I'll see you somewhere down the road. It's been a f****n' pleasure."
Alan McGee, who originally signed the band, predicted they would not tour together again for another five years or so.
"This is the most serious it's ever been... Noel's a proud person, he won't go back on it. And he knows he could make a successful solo album," he said.
The group's spokeswoman said: "I expect in the next couple of days a decision will be made as to how to continue or if they continue."
Johnny Hopkins, the band's spokesman from 1993 to 2000, said a break may do the band good, but suggested it may just be another of the many instances over the years in which Noel or Liam has walked out.
He said: "It's always been a volatile band. There have been regular incidents where one or other of them has walked off stage or walked out before a tour, but maybe it has gone a step too far this time.
"They'd probably benefit from time apart to develop their own things. If this is a real split rather than a temporary blip, they're bound to come back together at some point."
They were expected to play the Rock en Seine festival in Paris on Friday but the crowd were told by Bloc Party, who were due to perform before Oasis, that the Manchester band would not be taking the stage.
Many of the crowd thought it was a joke - until the big screens at either side of the main stage showed the message "as a result of an altercation within the band, the Oasis gig has been cancelled".
Ben Clover, 28, who travelled from south London for the festival, said: "I was hoping to see the band on the top of their game - now I am not sure we will ever see them perform live again.
"There are a lot of British Oasis fans who have come over for this gig and they are very disappointed."
Mr McGee described Noel's departure as a "sad day for music".
The founder of Creation Records, who discovered the band in 1993 when they performed in his native Glasgow, attributed the split to a "change of consciousness" that meant money was no longer enough to motivate people.
The Gallaghers' mother, Peggy, told the Sunday Mirror she was hopeful her sons would patch up their rift.
She said: "They do love each other, but they've always been very different. The funny thing is, they didn't fight as children. They didn't fight until they started the band.
"I hope this isn't the end of Oasis. I don't think it is. They're just tired at the end of the tour. They've had fights before and got over it."