'One good thing about what I do now is that it has reacquainted me with fabrics I had forgotten,' he said, rubbing some material between his forefinger and thumb. 'Like Crimplene. Doesn't half make you sweat, but pop it in the washing machine when you get home of an evening and next morning it comes out completely dry and ready to wear.'
Five hours later, Mike emerged on to the stage of the students' union bar at King's College London, wearing enough nylon to keep ICI profitable for the rest of the decade. He was also wearing a false moustache, heart-shaped sunglasses, a towering busby of an Afro wig, and a pair of platforms bigger than anything they've got at Paddington station. Instead of laughing, the 800 or so undergraduates crowded into the place greeted him as they might Axl Rose or Jon Bon Jovi. As his alter ego Mike Fab-Gere, confused rock legend, Southon has become the biggest draw on the college rock circuit.
'Hello, peace and love,' he said, flashing V signs. 'We are Mike Fab-Gere and The Permissive Society and this is 'Twentieth Century Boy' . . . '
The moment that his band, made up of veterans of Iron Maiden, Toyah's backing group and the orchestra of the disastrous West End musical Which Witch, expertly struck up the opening chord of Marc Bolan's song, everyone in the bar started dancing. And they didn't stop until, 90 minutes later, Mike and the boys pounded out the conclusion of Led Zeppelin's 'Rock and Roll'.
'Normally, this sort of thing's total shite,' said a boy in the gents afterwards, his shirt glued to his chest by sweat. 'But I tell you what, this lot are bloody tight.'
At 39, Mike is exactly 10 years younger than Mick Jagger ('we share a birthday and have a lot in common. Except Jerry Hall') which, he says, means no one can accuse him of being too old for his new profession.
Mike has been obsessed by rock since he ran the Progressive Music Society at Wellington College, Berkshire, in 1970 and persuaded Genesis and Hawkwind to play at the public school. He had been in semi-professional bands since his student days and in 1991, financially secure after he and his partners sold their computer training company for pounds 7.5m, he decided to make a career of it.
Other millionaires might have chosen to buy a yacht and sail the world, or buy a football club and sail to the bankruptcy courts, but Mike wanted nothing more than an appearance on Top of the Pops. 'I know these days it's all crap rave bands no one's ever heard of,' he said. 'But it still means everything to my generation.'
And there was nothing haphazard about his quest for an invitation. 'When I was in bands playing at Oxford May balls I grew to appreciate you have no more than five minutes to make your mark on an audience. And nothing got people going better in those first few minutes than old Sixties and Seventies numbers. I came to the conclusion that what was needed was a purpose-built retro band, playing oldies. Besides, I hadn't an original tune in my head.'
And so Mike Fab-Gere was born, by coincidence at about the time that tribute groups such as the Abba-alike Bjorn Again came to prominence.
Mike hired a stylist to give him the look ('it's the Seventies as you imagine them; I think people would have laughed themselves silly had I walked down the King's Road in this lot in 1973') and brought in a top-notch bunch
of rock musicians to whom he gave appropriate stage names: Andy 'Snake' Hipps, Richard Keiths and Bobby Skurll (as in
the song: 'I wish I was . . .').
He then employed the marketing techniques he'd learnt in computing and sat down to work out where he could play. The student circuit offered the largest number of gigs, so he tailored his product carefully to that market.
'The biggest problem colleges have, I discovered, is with the 'rider', what bands expect to be supplied with in their dressing room,' he explained. 'Some really take the piss, demanding crates of vodka and expensive food they never touch. I tell college entertainments' officers we don't have a rider. I reckon it saves them pounds 200 straight off, and generates about pounds 500-worth of goodwill.
'I drum it into my band that they must behave themselves and we'll be invited back year after year. Of course, arrangements get cocked up on the college circuit - they're students, after all. But there's never any histrionics from Mike Fab-Gere.'
Such attention to detail quickly paid off. At first Mike offered his services for virtually nothing and offered all sorts of inducements, such as free condoms for every concert-goer. But, within a year, he had established such a reputation that he was in danger of making a profit.
'I put in the early investment, supported it from the start,' he said. 'Now it's beginning to stand alone. The thing is I'm relaxed because I don't have to make a living at it, and I can afford to plough the money back in, pay the band well. If I'd been 20 years in the business and was still churning them out on the student circuit, it would really show on stage. As it is, I never thought I'd be up there with such good musos. I'm having the time of my life.'
Mike was clearly having a good time at King's. He had the cream of Britain's youth shaking every limb, word-perfect as they mouthed along to 'The Time Warp', 'Brown Sugar' and 'I Saw Her Standing There' - stuff that their parents would have been embarrassed to dance to, numbers that were hits before they were born. Mike will play another 50 or so college gigs this year. It seems he has, as they say in marketing, identified a niche.
The King's audience certainly thought so. At one point, Mike invited a young woman up on stage to help him with what he called a 'safe-sex demonstration'.
After ascertaining that her name was Jackie, he produced a giant Swan Vesta match and a condom, and invited her to put one on top of the other. She expertly ripped open the condom's packaging and, to much applause, rapidly unfurled it over the match.
'Jackie,' said Mike, when she had finished. 'To us you're more than a safe-sex demonstrator - you're the . . . Wild Thing.'
As Richard Keiths churned out Reg Presley's ageless riff, the audience went, well, wild. So did Jackie. Grinding her hips into Mike's, she arched over backwards invitingly as he leant over her and sang about how she made his heart sing. For a moment it all made sense: you would be hard pressed, if you were nearly 40 and completely grey, to think of better ways of spending a million than grooving up on stage with a hot little number like Jackie.
After the concert and out of costume, Mike repaired to the bar for some refreshment. Jackie was ordering a drink. Had she enjoyed it? he asked.
Had she fancied Fab-Gere himself? he probed.
'I thought he was fab,' she grinned, clearly not spotting that the man whose loons she had been mentally removing a few moments earlier was now, shorn of wig, 'tache and kaftan, asking her some personal questions.
'Mike told me to tell you he thought you were fab, too,' Southon shouted at her back as she walked away. She smiled politely over her shoulder.
'I love wandering through the crowd after a gig listening to what they thought and seeing if anyone recognises me,' said Mike, sipping at a lager and watching Jackie disappear into the crowd. 'No one ever does, of course. Why should they? I'm a sad old computer man. It's the wig, you see, that does it.'