I’ve just killed my best friend. She was lying on a sheepskin at the Portman Vetinerary Clinic. No one, to her relief, examining her; and the people she loved most around her. My daughter’s spaniel Velvet was trying, as usual, to grab food. Jenny’s head was in my hand; her difficult hind legs tucked underneath. My other hand held delicacies known to cognoscenti as Pet Tabs. “You could go on till she’s completely incontinent, back legs totally paralyzed,” said Baz. “But it would only be a few weeks. We can stop now while she’s not in distress all the time.”

Jenny was a labradoodle, a Poodle-Lab cross like a badly-permed labrador. I knew her sixteen years, one month, three days. When she was a six weeks scrap of timid black fluff I paid twenty pounds for her in an Islington pet shop. She bestowed her humour and enthusiasm on everyone she met. Not always to their liking – we never cracked that jumping up thing. But I was the career she never lost sight of, till yesterday. For sixteen years she slept under, on, or beside my bed. Her head went up every time I left the room. Meeting her eyes was as familiar as looking in a mirror. Every book and poem got written with Jenny beside me. When I was up all night this year for a book deadline, Jenny kept staggering in over the just-printed pages, cataracted eyes crying, “Why aren’t you in bed?”

When she went deaf I was pole-axed. She’d been so passionately responsive to every note in my voice, barked at every popping wine cork, and the only word she disobeyed was “Stay” – Barbara Woodhouse didn’t mention teaching dogs to be alone: I took Jenny everywhere. At a Duckworths’ party she snuck from my arms like a conger eel at a vagrant mullet and grabbed a canape off the editor of The Listener. “Wasn’t she quick?”, he said admiringly (thinking, no doubt, of his contributers).

Jenny was a terrible worrier. Her anxiety chewing shredded my best dress (she saw me packing a suitcase) and the car roof (in a thunderstorm). In the frozen blue twilight of the fen she ran away from a snowman. It was rumoured she fled from a rabbit but she was only running in the opposite direction. On Bonfire Night I read to my daughter in the cupboard with a torch, Jenny quivering between us. She trembled at parties even when she no longer heard balloons burst.

But she had a fantastic sense of humour. I never knew when she was taking the piss. “I want it, Jenny!” you lied. “What a fierce dog!” She growled delightedly, attacking the slobbery rawhide with extra passion. But who was humouring who? She loved all games. She was a star at Trumpington Dog Training Club’s Christmas party. In “Musical Chairs” you walked around, hound at heel, then leapt on a chair, hound on knee. It was between us and a bloke with an Alsatian. I got one haunch on the last chair, but we were shoved off by a large male posterior.

At a dogshow called Scruffs, Jenny won Second Prize in “Dog The Judge Would Most Like to Take Home”. For “Dog Most Like Its Owner”, my husband suggested my harem trousers (“Jenny’s style”), but we were beaten by an owner-dog team in matching sunglasses. In “Agility”, Jenny wouldn’t run round off the lead. “Jump with her,” said Gwen, but everyone laughed after the first hurdle. “What is it?” I said. “We jumped OK”. “Yes,” said Gwen, stifling giggles. “But look at your trousers!” Those harem things were round my ankles. When Gwen tells this story she adds, “And mum wasn’t wearing pants”. I usually skip that bit. My tights were fine. But when we finished the course, someone gave me a T-shirt saying “BEST IN SHOW”. Oh Jenny…

Jenny’s main aim in life was to be, always, with me. My computer exiting WordPerfect meant me going out. Would it be with her, or without her? Yesterday, it was her going out without me. Amanda, the nurse, and I went through it on the phone. Jenny falling downstairs, hind legs flailing on slippery floors. Shit in the house. Shit on beds. Anyone you love, you take the shit with the champagne; with dogs the shit is literal. It slid helplessly out between those terrible back legs.

It was three in the morning when I knew we couldn’t go on. The moon shone through the apple tree on Jenny falling over, trying to turn round. I walked out barefoot to rescue her. Some dogs are in obvious agony. Jenny had aches, humiliations, and baffling weakness which could only get worse.

She went out happy. Many people die in pain and fear: dogs are luckier. When you pick that puppy, you take responsibility for its life, shit, and death. That morning, I took both dogs on the Heath. Squirrel hunts for Velvet, sniffs for Jenny plus a canter in the wind till her back legs gave way. She bummed a titbit off an old lady. I found smoked salmon in the fridge. (“Oh God, diarrhoea,” I thought. Then, “In an hour’s time that won’t matter.”) We shuffled to the vet through drizzle. “Thanks, boy”, said a hairdresser sourly, watching her sniff his steps. “She’s a girl,” I said. “She wouldn’t dream of insulting your door-post.” We came to a main road. “You’ll have to carry her”, said Gwen.

At the vet Jenny looked longingly out of the window. “Have some water,” I said. I dipped my finger in; she licked that. Then she licked my cheek. She died eating Pet Tabs – canine caviar. Amanda held her secure. Reaching for another gourmet crumb, Jenny never noticed Baz’s needle in her fore-paw. Before it came out, her tongue relaxed, her head sank into my hand, muzzle down like a bird’s beak on its breast in the nest. Her eyes stayed open. (That’s what you’ve got to watch, emotionally – it’s upsettingly not like going to sleep.)

Velvet wriggled after the abandoned Pet Tab. Baz took off Jenny’s collar and held a stethoscope to her chest. The shot is simply a big dose of anaesthetic. After twenty seconds it’s round her body. “That’s it”, said Baz. “Her heart’s stopped.” She lay on the sheepskin as she often lay, quietly thinking things over. Velvet was completely uninterested, except in crumbs.

I’ve seen dog cemeteries in gardens of a Venetian palazzo, and under rhododendrons on the cliffs of Port Meirion. The back pages of dog magazines are packed with commemorations. We’ll get Jenny’s ashes – but where do you put this grief? Will this ache in my throat when I think of even her collar, curled in my drawer, ever stop? I cancelled parties and spent the evening with Velvet on my lap.

A dog enshrines all your memories: family, friends, self. Sixteen years is a lot of history. Gwen is fourteen tomorrow. Before she was born, we put a baby carrier on the floor: Jenny circled it, sniffing, then curled up in it like a sea-horse, muzzle down, tail under. History apart, there’s that unique personality: watchful, enthusiastic; generous, anxious, quick. We think of sentimentality about dogs as Victorian. Kipling was the maestro:

Dog-grief is way older than Kipling, though. Twelve thousand years since we turned olves into dogs. “Don’t laugh at this monument”, says an ancient Greek tomb, “although it’s for a dog. Tears fell for me, earth was heaped above me by a master’s hand.” These tears are ancient. Let them fall, sod anyone who doesn’t understand. “She had that perfect nature”, said my husband as we all (except Velvet) hugged Jenny on the sheepskin with her bright, dark, open eyes. “Such a special dog”, said a friend.

She never bit anyone; except me, once, trying to hold on as I left the car. It was only a bump with her teeth; which were, she thought, all she had to hold me with. Little did she know. The earliest domestic dog skeleton is 10,000 BC at Ein Mallaha, in Israel. But it has company. The dog, smaller than Jenny – more spaniely, I’d say – is curled up. The woman with it has a hand resting gently on its rib-cage. I know exactly how they felt.