The loyal followers arrived in droves at record stores across the country to hear the band's latest album Be Here Now for the first time. It does not go on sale until August 21.
Fans queued outside the Virgin stores where the album, almost a year in the making, was being played on their radio station at 8.30pm.
The band has said Be Here Now is the most important album of their career.
The band's songwriter Noel Gallagher said: "It's the one that's either going to send us up to U2's level or see us back on the dole."
He predicted the long-awaited third album would be one of the most important in rock history.
He said: "When it's all done and dusted, our band will go down in history as one of the greatest of all time.
"That is not bravado, that is fact. We will not be a footnote - we'll be a footprint in the history of rock music.
"We want to blow every band into oblivion. I suppose we are saying, `right move over now, the big boys are back in town'."
Only a handful of reviewers have been allowed to hear the hallowed tape, and they have had to sign detailed Creation Record contracts promising they will not play it to anyone else or even discuss it.
Music Week, the authoritative trade magazine, said Be Here Now is "worthy of all the anticipation ... epic, anthemic and massively commercial".
Record retailers are counting on Oasis to revitalise the music market after a slow summer following the relatively low calibre of releases. Gennaro Castaldo, spokesman for HMV, said: "This is exactly what the music industry needs.
"There has been feverish anticipation. People are almost not being rational about it. Many have left deposits to ensure they get a copy on August 21."
HMV has ordered "hundreds of thousands of copies" and Mr Castaldo says he is confident at least one million albums will be sold.
Oasis has rationed radio stations to four of the album's tracks until Monday when they will be able to play the complete album.
Unusually, the album goes on sale on a Thursday, August 21. This is to coincide with its worldwide release schedule. But even three days of sales should see it comfortably at the top of the British charts.
The influences of Oasis' heroes the Beatles and the Labour Party are evident.
The cover is a T photomontage of yesteryear, incorporating many references to the Beatles. A Rolls Royce floats in a swimming pool. The registration plate is the same as the police van parked on the sleeve of the Beatles' Abbey Road album.
The song Magic Pie on the album borrows from Tony Blair's conference speech last year which looked forward to the new millennium. The lyrics contain the line: "There are but a thousand days preparing for a thousand years."Reuse content