We claim to love artists like Ken Dodd – so why can’t we respect their wishes?

I saw Ken Dodd perform only once: in December 2015, at the Civic Hall in Wolverhampton. I was on the road with John Cooper Clarke. We were in the 400-seater downstairs, while Dodd was upstairs in the big room. He started at 7pm. We started at 8. We’d both finished our sets, entertained the usual backstage mob of ex-punks (Johnny’s crowd) and English teachers (mine), and polished off the rider before we ambled upstairs to “catch a bit of Doddy”.

It was about 11pm by then, but he was still going strong, reeling off gag after gag after gag after gag after gag after gag after gag. At a quarter to midnight, he took a comfort break. Some people left, others got out their Thermoses and blankets. After 10 minutes he was back, and the sledgehammer of gags started up again. Some were awful, others brilliant. After a particularly inspired line, Johnny Clarke would reach for his pen and whisper: “Here, shine that skyper (Johnny’s word for a phone) over here, kid – I’m having that.”

I’ve never seen anything like it. Sure, it was an incredible feat of memory and stamina, but its sheer length turned it into a piece of performance art: a comment on the relentless brutality of the live entertainer’s life. There was something almost macabre about it, like a music hall version of Weekend at Bernie’s.

For fans of Dodd, the endurance test became part of the fun; it was his USP (when he was tried for tax evasion, the joke going round was that if they gave him five years, he’d ask for 10). It was like being slowly tickled to death. I couldn’t take my eyes off him. Until, of course, I could, because it was all too much. We lasted about an hour, then went to our hotel (“That’s enough Doddy for one night”). Apparently, Ken pushed on through until gone 1am.

The sorts of gags and songs Dodd performed were certainly deemed conventional – downright old-fashioned, even – but that brief encounter with him left me with no doubt that he was a pure artist. If he’d been a canny entertainer, he’d have honed his show to make it a more palatable two hours. Instead, he sacrificed commercial viability on the bonfire of his obsession with being on stage. It defied convention, pushing the boundaries of what was deemed acceptable, and in so doing exposed a vulnerability.

This image of him matches what we have learnt this week – that he left behind more than 1000 notebooks, full of gags as well as self-laceration over his addiction to laughter, which he feared was ruining his health and spoiling his act. They are no doubt the work of a wild and brilliant mind. I’d love to have a look inside, but the thing is, Dodd didn’t want me to. He left his widow, Lady Anne, specific instructions to destroy them.

Now, who knows what goes on between a husband and a wife. Maybe Lady Dodd saw through his destructive desire. Maybe she knew best. Us artists are a temperamental lot, after all. Perhaps she had in mind Dante Gabriel Rossetti, who, in a gesture of sacrifice, consigned to his wife’s coffin the only copy of his manuscript of poems, only to dig them up seven years later when he wanted to publish them. But either way, Lady Dodd did not destroy the notebooks, and now they’re the centrepiece of a new exhibition at the Museum of Liverpool, dedicated to one of the city’s most famous sons.

I’m sure Lady Dodd means well. She wants to preserve the genius of the man she loved. I have no doubt she misses him dearly, and I have no desire to use these pages to throw criticism her way. However, I do wonder about the tendency we have to exhaust the artists we love: combing over DVD extras, listlessly scrolling bloopers, demanding ever more “personal” content on social media. We’re not content with being in the audience: we have to fight our way backstage and sniff the seat in the dressing room.

Wilde famously said: “To reveal art and conceal the artist is art’s aim” – to which we now say, “Shut up, Oscar, I’m reading his diary.”

It’s true that artists can use this ghoulish urge to their advantage (Picasso always paid his bills with a cheque because he knew the proprietors were more likely to frame it than cash it), but there’s a sense of entitlement that sits uneasily with me: that because we once bought a ticket to a show, we deserve a level of intimacy with the artist.

Besides, it all just misses the point. Posterity is overrated. Leave it for the politicians. What Dodd did was ephemeral – it lived and died in the moment. Together with his audiences, he created a magic that danced around in the rafters of civic halls and theatres. A magic that will never be seen again, and is all more precious for it.