If all you wish is to be gently charmed for a few hours, The Hotel Avocado will pull you along with it. As a comedian, Bob Mortimer spins a shaggy-dog story like nobody else, and this is a rollicking old-school yarn. It is full of splendid phrases (“dingy limpets”, “corned beefer”, “pudding drink”) and cheerful narrative cul-de-sacs. Does the plot hang together? Not strictly speaking! Are the characters in any way real? Not really! Does either of these things matter to the general sense of romp? Well, if they did, it would be churlish to say so when Mortimer is having such a good time. If you loved his first novel, The Satsuma Complex, you will probably have a good time too.

Sequels are famously difficult, something Mortimer deals with by summing up the events of the previous novel in gleefully silly sentences: “You will probably remember that I was shot in the hip by my ex-boyfriend Tommy Briggs just before he killed himself on the back lawn of the house he had imprisoned me in. Well… I’m 99% back to normal now.”

“Normal” is never the word that comes to mind about Mortimer’s work: The Hotel Avocado is both totally affable and genuinely bonkers. We return to the world of legal assistant Gary, his girlfriend Emily, elderly neighbour Grace, dog Lassoo, feral animals, corrupt cops and gangland baddies. Move the location from south-east London to Brighton, swap out the talking squirrel for a talking pigeon, throw in an enormous fibreglass avocado and we’re off to the races for more, basically, of the same. The book is narrated mostly by Gary, with occasional cameos from Emily, Grace and the mysterious talking stranger watching them from (under) a park bench. Emily has moved to Brighton to run a hotel. Gary remains in Peckham, where he is being threatened by the unsettling Mr Sequence: Gary is due to give evidence in a corruption trial, and Mr Sequence would rather he didn’t. From there, the plot spins on, largely out of control, and completely unbelievable. Or is it?

With Mortimer, as fans of his panel show appearances will know, the unbelievable is very often true. “The situation in my mouth is that I have one very long piece of teeth”, for instance; or “I once set fire to my house with a box of fireworks”. Mortimer lives in a world of sentences and situations that sound like obvious nonsense but are absolutely accurate. His subject is always really the insanity of the everyday, and it’s in his most granular renderings of the mundane that this novel works best: an overeager barista listing coffee roasts from light-light to dark-dark and everything in between; an evil henchman outside a cell door watching Ace Ventura: Pet Detective on a laptop while his victims struggle against their bounds; a housing tenant obsessed with non-existent damp as a kind of surreal reflection of grief.

And the parts that ultimately ring most true are the parts that sound most bizarre: the talking squirrel as a reflection of Gary’s loneliness, or Emily’s dedication to hoisting a five-foot avocado up a hotel flagpole as the pinnacle of her complex feelings for her late, estranged father. There is something very sweet in the way Mortimer writes about people, their feelings, and the weird things they do because of their feelings: a real tenderness towards the world, and the stories within it. Mortimer, you sense, has really paid attention to life. This is, after all, how you amass the kind of stories he is famous for telling.

But telling a story is not the same as writing a novel. Mortimer’s attention stands him in good stead as an author, but he can’t quite let himself inhabit his characters completely: he is always Bob Mortimer doing a bit. As a comic, as a storyteller, and now as a novelist, the man loves to gently wrongfoot his audience. There is a persistent sense that you are, perhaps, being carefully and tenderly made fun of. Bad guys get shot and shout “Aaghh! It hurts so bad!” Good guys shout “Viva tomatoes!” as their rallying cry. In lieu of a proper conclusion, a pigeon comes to explain what happens to the characters Mortimer forgot to write endings for (no, really). “Sorry, but yeah, there is a loose end,” signs off the pigeon, “and if that upsets you then post your complaint to the nearest harbour master.”

If an amateur wrote this, would it be … a bad book? If a beloved comedian does it, does that make it a good one? Is this another celebrity cash-grab taking up space in the book charts, or a sophisticated, sweet, silly meta-commentary on thrillers? When we review comic novels, is it the “comic” or the “novel” that matters more? And, most of all: does any of this actually matter if you’ve had a nice time?