You haven't lived until you've seen him "live". That's the deal with Ken Dodd, surely the most extraordinary performer of our day and certainly the oldest, pummelling the circuit around the country from Barnsley to Bromley, York to Yeovil, now in his 84th year and still no signs of weakening.
Endurance – his own, as well as that of the audience – has long been the predominant theme.
As we kicked on towards midnight in the Stockport Plaza the other night, he said: "Most of you have been reported missing by now," adding that, if we had an MP's expense account, we could put the wonderfully renovated art deco interior down as a second home. And charge for the paintwork.
Why does he still do it? When I asked him this after the show – it was well past one o'clock and a few of us had gathered in the front stalls, with beakers of champagne and red wine, while the volunteer staff hoovered up and collected lost scarves – he fixed me with a look of amazement.
"What else would I do? There's nothing like the sound of laughter to keep you going. It's as simple as that, really. It's better than Sanatogen. And I never get tired of seeing different parts of Britain. I had no idea, for instance, how many castles there were in Berwick-upon-Tweed, did you?"
He's an immensely courteous and curious man. I'd taken along two friends who had never seen him live and he made them feel like old pals.
He's like that with everyone, except possibly the tax inspector (he was charged with tax evasion in 1989). And he was full of the joys of lately going down the Nile on a Jules Verne cruise. Can you imagine sharing a dinner table on a holiday trip with Ken Dodd for two weeks? He told one of his fellow diners that his partner, Anne, was a good cook. "Her pea soup's the best ever." It was only at the end of the excursion that the lady opposite plucked up the courage to say that she didn't think you could get herpes soup.
Anne Jones is also his onstage second billing (she does a 20-minute romantic and Country & Western favourites spot with keyboard and guitar to break up the first half of three-and-a-quarter hours), his wardrobe mistress and his stage manager. They've been together for half a lifetime, never married, have no children and live in the same house in Knotty Ash, Liverpool, that Ken was born in; his dad was a coal merchant, the house full of dust, hence the asthmatic wheeze and constant liquid cough. They will be driving home from Stockport later on. Wherever they are, they usually drive home. Occasionally, they don't mind using Travelodge hotels as they welcome dogs: Pippin George, the black poodle, goes everywhere with them, though he's lately taken to suddenly biting people. The audience bites Doddy, too, he reckons, if he's not at his best every single time he goes on the stage, his natural habitat. The attack, elegance and sheer verve of his performance are as strong as ever, but I've noticed something else, too: an increasingly mellow amalgamation of the rapid-fire funny stuff with the sentimental reflections and balladeering.
It's an unaccountably moving experience for the audience to watch this Scouse master clown, the very last one of our past and modern ages, pad gracefully towards the grave on our behalf, taking with him the Merseyside music hall tradition he litanises towards the end – Robb Wilton, Tommy Handley, Arthur Askey, Ted Ray. In the act, he recounts how people greet him in the street with a cry of, "Are you still here?"
This is the old man who defies the ageing process, the Peter Pan who's become the humorous laureate of the elderly and the elderly-in-waiting. There's a lot of Samuel Beckett about him these days, something defiant and elemental, the cackle in the dark.
Dodd started out in showbusiness as a ventriloquist. His vent turn with Diddyman Dicky Mont in the show's twilight is also the highlight and not just "for the kids". It's a conversation between an old man and the son he never had; the carpenter and Pinocchio. "What are you going to sing?" Dodd asks Dicky: "What do you know?"
Dodd may now be a sex symbol "for women who don't care" and a spokesman for patients in the overstretched NHS, where he can't even get a corridor to himself, but he's also become the tribal fabulist who spins yarns of Chaucerian saltiness – including the one about the nudist camp in Glasgow where they charge you; it's a "Pay and Display" – and a backstop to our primal fears of transience and decay.
Early on, after soliciting the usual ribald response from the ladies in the audience when asking if the men of Stockport are good lovers, he declares that the town was built on the Garden of Eden. He then sings: "When I grow too old to dream, your love will live in my heart." Ten seconds earlier, you were crying with laughter. Suddenly you're just crying.
"Tears (for souvenirs)" was Dodd's chart-topping song of 1965 – it knocked his fellow Merseysiders, The Beatles, off the top spot and stayed there for a record-breaking six weeks – and it's the musical B-side of his trademark number, this show's finale and the tour's subtitle – "Happiness".
Happiness, happiness, the greatest gift that we possess... it's simple, it's slightly calypso (with Dodd doing a joyful descant to our singalong-a-clappy chorus) and it's utterly irresistible.
The reason I try and see Dodd at least once a year is that he provides an experience of ecstatic liberation in the theatre that nobody else does. For a few hours, he binds an audience tighter than a diet of boiled eggs for a fortnight ever could. And there's no escape, even when you leave the cocoon of his comedy. If we don't laugh at his jokes, he threatens to follow us home and shout through the letterbox. It's not television: "You can't turn me off, missus."
That's a trademark line. One or two of the routines are always the same, too: the farmyard noises, the heartfelt song to "absent friends", and the hilarious "Granada" item, Dodd's sombrero decorated with bouncing ping-pong balls and his teeth clacking like maracas.
All of it sounds familiar, but my inventory of the material at the Stockport performance is very different from one I kept in Bromley several years ago. Bromley incidentally, he said, wasn't twinned; it had a suicide pact with Grimsby.
Sex is no longer what posh women keep their coal in; it's a safety hazard, and safe sex is a possibility only if you've got a handrail round the bed. He's ironing out the grotesquerie, though: no longer does he suggest making a Rollo last a fortnight by putting in your teeth back to front.
He once claimed to add six new gags in each show. And there used to be more topical references. In Stockport there was a reference to Lady Gaga, but otherwise we could have been back in the late 1950s; we even had a man playing the mighty Wurlitzer organ, rising from the pit in the interval.
Young comedians? They mean well, he says, but he doesn't like the language. "I blame the parents. They shouldn't give them fizzy drinks."
I once asked him for his definition of an alternative comedian. "One who isn't funny," he said. But you can't say he's a member of any establishment except the old variety school. He's too strange and bizarre for that.
He was a great admirer of Mrs Thatcher and is proud to have made his peace with the taxman ("Self-assessment? I invented that") and to have received both the freedom of his native city and the OBE ("One Boiled Egg").
I ask him about politics and the coalition government. "The collision government? There's no level of interest among ordinary people. They want to know if so and so's wearing a frilly nightie, or can she cook, or where their next holiday's coming from."
And he hates the degree of snooping intrusion into people's private lives, Wikileaks and so on. He even goes so far as to say he feels sorry for John Prescott.
And with that, the Squire of Knotty Ash is at last calling it a night and heading home. Anne does the driving.
The big grey car standing outside the Plaza is loaded, the costumes and props all stashed, and the endless – never a farewell – tour continues.
With any luck, Doddy will be in a theatre somewhere near you before Easter: Bolton, Dudley, Blackpool, Leamington Spa, Basingstoke, Buxton...
Sixty years of gags: The wit of Ken Dodd
"I knew we were going to war in Afghanistan. I passed Vera Lynn's house the other day and she was gargling."
"My life has been a series of tragedies, culminating in tonight."
"If you're watching my lips you're laughing at a joke I'm not even telling; we'll be related by the time you leave this show; go on, look under your seats, and you'll find a will form."
"We're about half-way through [it's 11.45pm]: it's time to break open the packed lunches! This isn't the telly, missus, you can't turn me off."
"I used to perform twice nightly. Well, so did most men..."
"Income tax used to be a penny in the pound. My trouble is, I thought it still was."
"After fourteen minutes at the Theatre Royal, Barnsley, I got two laughs. Two's good: they let you live."
"I've had problems, but nothing compared to the trapeze artist with loose bowels."
"I took a girl to my allotment and showed her how I force my rhubarb."
"Last night, the act before me was so bad that they were still booing when I was on."