'THIRTY years," mutters Suggs from Madness. "Thirty bloody years I've been wiv 'em." For a moment I think he's talking about his band, those baggy-trousered nutty boys; turns out he means his bank. They kept him waiting an hour and a half, despite three decades as a loyal customer – "and despite us shooting some of our best videos there as well".
But that's not the whole story of his tardiness for our rendezvous at Quo Vadis, his Soho club. En route from his home in Camden he bumped into Graham Coxon from Blur and an earnest discussion about the perils of the rock reunion soon necessitated strong drink. And there was another impediment for Suggs – an injured hand.
"Last night I was on the Mall with Buckingham Palace up ahead and Admiralty Arch – where John Prescott bonked his secretary – behind me and I just thought: 'London, my London – what tales lie therein.' So when I saw this big pile of leaves I was so exhilarated that I just dived in. And that's how I hurt my hand."
Days can sometimes blend into nights for Suggs. I deduce this from the following greeting to Quo Vadis's manager: "Oi, Eduardo! You're still wearing last night's shirt with last night's stain – you dirty slag!" And once a day/night at least, he probably begins a sentence thus: "London, my London..."
London has always featured in Madness songs and they've marked their 30th anniversary with The Liberty Of Norton Folgate, something of a London concept album, earning the band – Edinburgh's star attraction for the world's biggest Hogmanay street party – the best reviews of their career.
But how does Suggs respond to all London-loathers who think it too big, dirty, expensive, impersonal and up itself? "I'd refer them to a recent edition of the New Yorker magazine which said that ongoing right now is 'an experiment of assimilation and immigration the like of which the world has never seen'." An erudite defence, it's true, but what I really want to talk to Graham McPherson about is Scotland.
That's his real name, though he's been Suggs since his schooldays. "I was an ethnic minority of one. The mix was Chinese, Pakistani, West Indian, Irish, a small majority of English – and me, the only Scot." Didn't that make him feel special, unique? "Not when I was being called a smelly haggis c***. So I changed my name. I was into graffiti so I needed an alias anyway. I got Suggs from my mum's encyclopedia of jazz musicians – she sang in the pubs – and I wrote 'Suggs is our leader' on the walls. Kids used to say to me: 'Are you the Suggs everyone is talking about?' I created my own myth."
His mother Edwina is Welsh and she still lives close by; his father, William Rutherford McPherson, walked out on the family when he was three, and Suggs grew up in some hardship in London bedsits, occasionally being packed off to an aunt in Wales when his mum couldn't cope.
What became of his dad? "I don't know, but what I've heard hasn't been good: heroin, injecting his eyeballs with paraffin, being sectioned. He must be dead now. I mean, he would have got in touch if he was alive, wouldn't he? Yeah, he must be dead, poor bugger."
We're drinking beer on Quo Vadis's balcony. The club is a splendid establishment but the al fresco facilities are somewhat modest: a plastic table and two chairs on a rusty iron ledge, underneath a thrumming generator. "Lovely what you've done here, Eduardo," says Suggs, to which mine host replies: "Amazing how far 15,000 quid goes." A well-worn comedy routine, no doubt, but then he returns to familial matters.
"I never tried to find Dad when I was younger because very quickly I got married and became a dad myself and there just wasn't the time. But a few years ago I took my girls up to Newtonmore on a camping roots trip. That's where the McPhersons hail from. I met three other Graham McPhersons, which I was really chuffed about, although I mustn't come over all Rod Stewart about my tartan heritage. All my Irish pals grew up wanting to be someone else. They got fed up seeing collection buckets being passed round the pubs for the IRA. An over-sentimentalised attitude can be dangerous."
The best Madness songs are happy/sad, party beats broken up by serious lyrics, mirth mixed with melancholy – and Suggs in conversation is exactly the same. He can be Max Wall music hall about London; he can be as studious a chronicler of the city as Peter Ackroyd and Iain Sinclair. And while he's enjoying being the cheeky-chappie Cockney today – ordering Eduardo to turn off the generator so when he calls home his wife won't know he's at the club, again – there are a fair few moments of introspection and self-examination.
His wife Anne was his teenage sweetheart. In her own pop life she was Bette Bright, who had a 1978 hit with My Boyfriend's Back. "It didn't work out for her after that," he says. "She asked me if I wanted to have kids. I was still only 19, still a buffoon. I said: 'You'll have to look after them because I ain't stopped.' But I'd like to think I've been a good father to them.
"It would be patronising to my family to say I wanted to be around for them because my dad wasn't for me, but it was a bit like that. When I found the right woman I was determined to make it work – that it wasn't going to end up in the same mess that the five previous generations of this clan had experienced."
It's probably not coincidental that, with his daughters Scarlett, 26, and Viva, 24, having moved into their own place and formed a band, Suggs now feels ready to find out what became of William Rutherford McPherson. While 2009 has been a very London year for Madness, with Suggs penning his own book about the city, their leader plans for 2010 to be quite Scottish.
"I've got the chance to do (BBC genealogy show] Who Do You Think You Are? but I want to write my memoirs. It's going to be a quest, to learn about my dad's story, and I don't want to say it's going to be some big therapeutic bollocks but that's exactly what it'll be.
"What did I miss about not having him around? Everything. It would have been great to be able to talk to him about all the stuff I've found difficult, like the journey from boy to man. That's still a bit of a struggle for me, to be honest."
And there he leaves the saga. Possibly that's enough self-examination for one afternoon. Or maybe he's just reminded himself that if he hadn't been that boy, that buffoon, sneaking into boozers to hear his mum sing, who fell in with a street-gang, most of whom had single parents – then his surrogate family otherwise known as Madness might never have happened.
In the year that a great singles band finally made a great album, acquiring maturity of their own, Suggs hopes the Hogmanay gig will be the perfect finale. From losing a shoe on the last bus home through nicking his mum's raffle-prize whisky to circumventing millennium traffic restrictions with strategically parked cars filled with bevvy, he says he can prove that the great Scottish festival has always been important to him. Then he checks himself. "Was that too much? Eduardo, was that too Rod?"
Madness play Glasgow's O2 Academy, 13 December; Edinburgh's Hogmanay, 31 December www.madness.co.uk
• This article first appeared in the 29 November edition of Scotland on Sunday