Since Peter had first left home in September 1997, to study English at Queen Mary, University of London, whenever I caught sight of him with his sleeves rolled up I would search his arms and eyes for the telltale signs of drug use. It was just something that I did.

But every search brought about the reassurance that he was OK. There had been no needle marks. No pupil irregularities. Not a word would be spoken because, as far as I could tell, there was nothing for me to worry about. As far as I could tell, he was safe.

I was already aware that Peter had tried cannabis a few years earlier. Since then, rather than keep asking questions that I felt would alienate him I thought it wiser to just use my eyes and ears.

During his first few weeks at university we had met for lunch at the home of Nanny London. The kids had always called my mother Nanny Liverpool and my husband’s mother Nanny London. He couldn’t wait to tell us all about his experimentation — we’d always had an open rapport, an honesty. So he and I went for a walk and a two-hour chat ensued.

I went mad.

“Everyone smokes it,” he told me.

“And that makes it right?” I argued. He hadn’t a leg to stand on. Hadn’t I always told him it was a “gateway drug”? Not every cannabis user goes on to take hard drugs, but statistics show that most hard-drug users began by smoking cannabis. “Mum!” he scoffed. “I’d never take heroin!”

Famous last words.

Peter had left home not smoking. Nanny Liverpool had smoked and he’d detested it. He didn’t like even to sit in the same room if she was having a cigarette. He’d won a local poetry award with a poem about smoking. “Cough cough cough,” he’d written. “Coughing up what shouldn’t have been there in the first place.” He’d won a cash prize, too — and now here he was, keen to share his rebellion with me. I was grateful for our long talk and honestly felt I’d made an impact. How foolish mothers can be. He was 19 and away from home. My son was now a smoker. Happily, in front of me, it was only cigars or cigarettes from a packet (I noticed, suitably relieved).

Nowadays I hardly ever see him without a cigarette in his hand, whether he’s performing or on a television interview.

To think I used to be concerned about cigarettes.

From the day of Nanny Liverpool’s funeral to Peter’s first rehab was eight weeks. Eight weeks of madness in Peter’s life. In those eight weeks Peter, my husband, had received a new Army posting and we had moved from Germany to Holland.

One week after moving, almost eight weeks since the funeral, the inevitable call came while I was on night duty: it was someone very close to Peter and the band, the Libertines, calling to tell me that he was way out of control; that someone now needed to take control, someone needed to be taking responsibility for him and his ever-increasing, drug-induced frenzies. Parental intervention was now required and they told me of the many problems that the band and all those around them had to endure because of Peter’s drug taking. The relationship, they said, was now untenable. Untenable? Drug-induced frenzies? What the hell were they talking about? Late for rehearsals . . . mood swings . . . bizarre behaviour . . . Why hadn’t I heard this before? Why had they left it until now to say parental intervention was required?