It's farewell then, to Oasis's "Binmen Years" and hello to the tub-thumping engine room of Alan White, Gem Archer and Andy Bell. "We're not Stone Roses MkII," they assure Michael Odell.

If the three men strolling through London's Soho were proper rock stars, then the British Gas road diggers in fluorescent jackets would drop drill and spade and demand autographs. They wouldn't be trying to reverse a truck into them. "They're in the way," grunts a worker as he watches the "other three" in Oasis have their picture taken. "Is he that Liarn fella;' The wrong 'un?"

Actually it's Oasis bass player Andy Bell, though with shades and feathercut he's easily mistaken for his Mancunian boss. "Don't recognise any of'em," shrugs the digger, returning to his mud. And so Andy Bell, Alan White and Gem Archer spectacularly fail the "mobbed by fans" controlled experiment.

After another short anonymous stroll, we take our seats in a crowded West End pub. In the lunchtime melee, pints and sandwiches are passed over a sea of heads, but still no hassle or hint of recognition. Never mind. Q's aim is to find out whether Oasis MkII is a real band: five rock stars rather than the famous old configuration-the two Gallaghers plus Tony McCarroll, Paul "Bonehead" Arthurs and Paul McGuigan, aka the three "bin men".

Thankfully, we can confirm that, yes, today's backroom boys are a different proposition. Gem Archer is every inch the gentle Geordie diplomat. Andy Bell - complete with shades and train driver headwear - is slightly gawky under pressure, clamping hands between knees when earnestness takes hold, but is the most frank when discussing life in the engine room. Meanwhile, oldest new boy Alan White is a pugnacious cockney who talks with chin proudly raised over his veggie burger. All three are individuals in their own right. "You think we've been asked to get an Oasis haircut?" laughs White, chewing on a piece of lettuce. "No! Noel hates us having the same stuffas him. Honestly. If he sees shoes he likes, he'll buy them all and then he'll buy all the ones in Liams size cos he doesn't want his brother to have the same ones. I'm not joking. He's deadly serious about it."

The trio's paths to Oasis MkII were all very different. "I was already an Oasis fan," says White, whose brother Steve has been Paul Wellers drummer since 1982. "I'd seen them on Top Of The Pops doing Shakermaker [in 1994] and didn't like the look of the drummer. I thought, I could do that a lot better. There were rumours of problems, but the last thing I expected was to get a call a year later. Noel just rang me and he said, Do you wanna be in Oasis?"

Meanwhile, Archer had been recording a new album with his hand Heavy Stereo, making "the best music of my life", when Oasis intervened in '99. He was in Newcastle visiting his seriously ill mother when he got the call. "I was at me mam's when I heard Bonehead had left. Next thing I know, Noel has called me house and a week later I'm at Olympic Studios in London hanging out as they mix Standing On The Shoulder Of Giants." The last limb sewn onto the rock Frankenstein was ex-Ride and Hurricane #1 guitarist Andy Bell who, in the summer of 1999, had retired to his singer-songwriter wife Idha's Swedish homeland to "get my head together and grow a beard". For six months the offers of work flooded in - most notably from indie glarnmers Gay Dad - in 2000. Gem Archer recalls riding in a car with Liam Gallagher when the news was announced.

"Liam yelled, Andy Bell's joining Gay Dad! We can't let him do that!" Within a day, Noel Gallagher was on the phone and Bell had flown to Wheeler End studio in Buckinghamshire. "I'd never played a bass before," he recalls. "They asked me to pick it up and join one of the biggest bands in the world. It was an offer I couldn't refuse."

With the revamped Oasis now taking shape, the new boys had to be "bedded in". For some this meant harmless nicknaming, but for posh southerners it took the form of merciless psychological torture. Shortly after joining Oasis, White became known as Dave, on the grounds that he once served the band a drink from an unattended hotel bar and therefore resembled "Dave from the Winchester bar" in the '80s TV series Minder.

By contrast, Bell was forced to run the gauntlet ofhis band and their audience shouting, "Who the fuck is Andy Bell?" at 2000's Reading Festival. "And just when I was getting the hang of the bass," sighs Bell, "Liam told me, You're only in this band cos you wear cool shoes. Anyone can play those bass lines."

Unsurprisingly, Bonehead and McGuigan are no longer in touch with the Gallaghers, but they have forged friendships with their replacements. White is in touch with both ("They're diamonds - and they bear no malice") while Bell went out on the town with his predecessor, McGuigan, in Stockholm a few weeks ago. "It was the first time we'd met since I replaced him and I was a bit nervous. I wondered if he was going to give me any attitude but he was cool. He made his choice and I think he's happier now" There seems little question the new boys have a better musical pedigree. But as Noel Gallagher explained in last month's Q interview, the nix of personalities and their lifestyles has been just as important to keeping Oasis alive. Noel Gallagher night have casually recruited them over a cup of tea, but was he sneaking a look at their nostril membranes at the same time?

"No one asks ifyou do drugs before you join,"says White. "I've never touched cocaine in my entire life. I know that sounds mad considering I've spent seven years with a band and half the audience off their tits, but it's true." All of which begs the question: could the new boys ever get away with misbehaving themselves? "Let's say we've got some credit in the tantrum bank," laughs Bell. "They've walked out on us in 2000, so we owe 'em one. But I don't know what would happen if I got pissed and disappeared for a couple of days." Archer reflects that on the last American tour he and a friend got "New Yorked" on a night off in Manhattan. During the ensuing show he was concerned that vomit was spilling from his mouth onto the front row, but no official complaints were forthcoming.

"That's all I can tell you - you can dribble puke on the audience. That's as far as I've pushed it, but walking out? Different ball game." Noel Gallagher's most spectacular deposit in the "tantrum bank" was made two years ago. During the summer of 2000, Liam Gallagher was the only original member of Oasis left. Oasis had been due to play in Barcelona but after an injury to Alan White's thumb the show was cancelled. Unable to leave town before their bus driver had his regulation kip, they drank the rider. Liam Gallagher then took the opportunity to make some observations about Noel's wife, Meg Mathews (whom he was then divorcing). "Something was brewing- you could feel it," remembers White. "Noel and Liam were talking and suddenly there's a hail of beer glasses and shouting and Noel and Liam trying to kill each other. I'm saying What's going on? and people are saying, Get out! Just get out! I've seen them fight before but this was different. It was darker and I thought, That's it. We're finished:"

The band eventually drove to Paris where Noel left the group, vowing never to tour again. After a grim meeting in a French hotel room, it was decided to continue without him. Guitarist Matt Deighton, from acid jazzers Mother Earth, was recruited for the remaining gigs while Archer was asked to learn all Noel Gallagher's guitar parts during an overnight bus journey to the next show. "We were driving through the Alps at night," says Archer. "I'm awake thinking, A year ago I was an Oasis fan. Now I've got 12 hours before I have to convince 20,000 people I'm Noel Gallagher."

But the sibling rift wasn't just an initiation for Archer and Bell into Oasis's dark side, it also appears to have been the making of Liam Gallagher. "Noel walking out gave Liam something," asserts Bell. "Liam thrived on having responsibility. He was focused and walked a foot taller. Because Liam managed to carry Oasis through those European dates I think he earned Noel's respect. And after that it was like he had this boost and he could say Right, I made it work. I saved Oasis. Now you better give me a voice in the band and take my own songwriting seriously." The European dates were completed to generally warm reviews, and when Noel rejoined the band's dynamics were changed. New album Heathen Chemistry became Oasis's first band project, Bell and Archer contributing their own songs and also urging Liam to mine his own creativity. "He wanted to write, but it takes him a while," says Archer. "You have to say, Put your finger there... on the guitar, but he gets great songs out of it."

"If you want to please him tell him it sounds like something The Beatles did," adds Bell. And yet it remains unclear whether the new boys were allowed to exercise the quality control that Oasis sometimes need. When asked by Q whether his bandmates expressed their honest opinion, Liam Gallagher was aghast. "Of course they fucking wouldn't," he claimed. Do they?

"Yeah... yes," says Bell. "No," retorts Archer, before continuing, "I mean, I'll give an idea everything'til it's finished and then we decide if it's good." "I don't think there was a song where anyone said, That's absolutely shit!" says White. "But we did disagree," continues Bell. "None of the songs we just started playing and it was like, Right, that's perfect. There was a lot of arguing over how to record songs. We're not session musicians being told what to play. We're not Stone Roses MkII:"

So, officially, they're not just there to crunch levers, but there is a moment's baffled silence and then laughter at Liam's description in Q190 of them as "Four great blokes from Manchester" (Alan White: "We're not though, are we?"). But there is a general agreement that Noel does answer to his own description of "the old mongrel who gets his nose in the bowl first". Without his vision and leadership Oasis would founder, they say. "He is the old mongrel but he's our eyes as well," says Archer. "Oasis is Noel Gallagher - no question. But I think even he'll be surprised at where this group of five people can take him"