John Lydon has never pulled his punches so any conversation with the iconic punk legend inevitably evolves into a roller coaster ride through different moods and emotions. When the singer – who transformed rock music in 1977 while fronting The Sex Pistols – is in mischievous mode he’s hard to beat.

My casual inquiry about his take on the recent Oasis split elicits the curt reply: "I know why people compare Oasis to the Pistols but the problem is there is NO verbal content. Noel’s words are just strung together for the sake of the melody." Ask him to sum up the adventurous music created by more experimental pop acts such as Radiohead or Coldplay and you’re hit with: "Occasionally those outfits come up with a tune which is quite nice but there’s a dourness and pomposity about them that turns my stomach."

And prod the star playfully about his starring role as a spiky-haired English farming oik in hilarious TV adverts promoting Country Life butter and he lets rip: "In these days of healthfood hippies, a pound of Country Life Butter is looked on as a notorious object. Just the thought of it would give the lettuce munchers a heart attack yet it goes well with a nice bit of salad."

But Lydon, 53, is more reflective about why he’s reviving his seminal post-punk band Public Image Limited after a 17-year hiatus. They’ll play Glasgow’s O2 Academy on December 18 as part of a tour to mark the 30th anniversary of masterpiece album Metal Box. You can only applaud Lydon when he’s honest enough to admit motivation for PiL’s surprise reformation is cash – and death.

John said: "Concert promoters phoned to say there were dates available, was I interested? So they put the money down, and I am. "For me, PiL is the greatest emotional release. It’s a wonderful way of profiting from my own family’s misfortunes. "The group began in 1978 with the sadness of my mother’s death. So it’s not really jumping on the bandwagon."

The passing of mum Eileen had a profound effect on the singer. He said: "She died of cancer, it was an excruciating death." His way of coping with the loss was to immerse himself in music and he was inspired to write PiL’s 1979 single Death Disco about the tragedy. Last year the singer’s father John died of a heart attack outside the home he shared with partner, Mary Irwin. The couple had an altercation with her son Gary – who they were trying to evict from their home – when John Snr took ill.

During that time John’s brother Jimmy was having chemotherapy for throat cancer, which is now thankfully in remission. John said: "The death of my father and my brother’s illness deeply upset me. It brought me straight back to Death Disco. I’ve never been able to cope with such loss very easily. "I wanted relief from it. The song gave me honesty. I suppose I’m a lucky chappie in that I’ve managed to find an outlet in my life where I can release all my angst... and celebrate my joys. "I went into a room, put on Death Disco and wallowed in it. I was shocked by just how emotional that record is and how bang on the money it was. I was able to take great strength from my music."

The 2009 incarnation of PiL will feature guitarist Lu Edmonds, bassist Scott Firth and drummer Bruce Smith. John said: "There have been 30 members plus in PiL over the years so who do you go to? I have a whole bunch of new songs. Maybe one or two will lend themselves to this little session."

He formed the group in 1978 in the wake of his volatile departure from the Pistols – Steve Jones, Sid Vicious and Paul Cook. Lydon – then known as Johnny Rotten – was the snarling singer whose stunning lyrics in songs such as Anarchy In The UK, God Save The Queen and Pretty Vacant not only changed the face of music forever but defined global pop youth culture.

When Lydon launched PiL – whose original line-up featured Keith Levene, Jah Wobble and Jim Walker – few music critics predicted lightning would strike twice. How wrong they were. John recalled: "With PiL, I felt I had more to do... emotionally, creatively and mentally. As sad as the Pistols fumbling into nonsense at that time was it didn’t mean my creativity level would stop.

"I didn’t set out to be different. It wasn’t deliberate. I know there are outfits out there who think, ‘Let’s come up with a jazz-fusion epic’. But I don’t see myself as Radiohead or Coldplay. With them, there’s a presumptuousness towards genius which is not well earned. They sound like K-Tel’s greatest jazz hits. I’ve heard it all before from them two. They’ve not created a thing of their own. It’s really tawdry."

PiL’s initial album releases – First Issue (1978), Metal Box (1979) and Flowers Of Romance (1981) were breathtaking in their ground-breaking innovation. The group’s string of hit singles include Public Image (1978), Memories (1979), This Is Not A Love Song (1983) and Rise (1986).

In 1986, Scots guitarist John McGeogh joined PiL and formed a solid bond with the singer. The innovative Greenock-born musician – who played with Siouxsie And The Banshees, Magazine, Visage and The Armoury Show – died in his sleep aged 49 in 2004. He is remembered with real affection.

John said: "I’d heard his work with Magazine and when we met we instantly got on like a house on fire. John’s music tastes were very different to mine but there was a meeting place somewhere in there and it sparked all kinds of new creativity. He was wonderful and I miss him like mad. John brought great personality to PiL. The humanity of the man was enormous."

Lydon lives in Los Angeles with his German wife of 30 years, Nora Forster. In 1996, he took part in The Sex Pistols’ Filthy Lucre reunion tour, making his peace with original bassist Glen Matlock. His autobiography No Irish, No Blacks, No Dogs was a critically-acclaimed best seller. Lydon also led the Pistols in a money-spinning reformation in 2007.

But he now wants to focus on PiL. He said: "I’m not even thinking about the Pistols. Everybody in the band is doing different things. It’s hiatus time. "I’m having problems with the Pistols, though, because I can’t seem to write songs for the band. "Once I put pen to paper and hum a melody I keep thinking, ‘That would be better for PiL’. I’ve put my a*** – and my money – on the line with PiL."

Lydon is counting the days until he plays Scotland. He said finally: "The Scottish culture and personality is so warm. Going there is one of the world’s highlights for me. I’ve always liked Scottish people, I feel at home with them instantly. We share old Celt traditions."

PiL play the O2 Academy, Glasgow. Tickets are on sale now from www. livenation.co.uk or tel 0844 576 5483 (24 hours)