Bernard has a bucket list. It’s not unusual to have one – many people do. But Bernard is not a person, he’s a dog. A dog with two months – three at the most – to live.

Our family – me, my wife, Tracey, and our children, Sophie and Adam – adopted Bernard, a white and tan Jack Russell, in 2008. He was raised on a farm and earned his keep as a ratter, and we weren’t convinced the little bundle of energy would fit into their cosy and relaxed home.

But Bernard slotted in perfectly straightaway with his warm and friendly temperament. He was fussed over by Tracey and Sophie, acted as a playmate for our youngest, Adam, and went on long walks with me along cliff tops, woodlands and beaches, chasing rabbits and seagulls he never quite caught.

Over the years, he became part of the family and we got to know and love his funny little ways. He never barked, except when he saw frogs and hedgehogs in the garden. He would attack the lawnmower, snapping at the wheels. And he loved playing with tennis balls, lots and lots of tennis balls, morning, noon and night.

Believing him invincible, we thought he’d sail through the average terrier’s lifespan of 13 to 16 years and make it to 18 or more.

The UK’s oldest Jack Russell, Meg from Somerset, reached the grand old age of 25. We wondered if Bernard might live as long.

And then everything changed.

In October, a regular checkup at the vet’s led to the discovery of a large tumour on his liver. “The size of a squashed orange,” the vet said. It was a malignant cancer, active and aggressive. The vet gave him two months to live, three at most.

I reeled at the news, barely holding on to my composure, struggling with tears as I paid the receptionist

I reeled at the news, barely holding on to my composure, struggling with tears as I paid the receptionist and finally breaking down as I reached the car. Bernard looked at me puzzled, his head cocked at an angle, as the tears ran down my face.

The hours that followed were a blur of telling Tracey and the children in turn. Hopes were raised as we trawled Google for “benign tumours” and dashed just as quickly as I spoke to the vet who confirmed the diagnosis. We came to the realisation that there was nothing we could do to save him.

In the following days, we worked through as much of what we thought would be on Bernard’s bucket list as possible – eating as many fresh-cooked sausages as he wants, throwing a tennis ball for ages on the beach and taking long walks through Rendlesham Forest.

Plans were made as we prepared for the worst to happen suddenly and soon. The symptoms, beginning with loss of appetite and excessive thirst, would escalate to vomiting and diarrhoea until his damaged liver finally left our old friend listless and in unimaginable pain.

Amazingly, Bernard then taught me one of life’s most valuable lessons – to live to the full today rather than thinking about tomorrow. I’ve spent my whole life looking forward to what’s coming next, the cinema tonight, the weekend trip away and the exotic summer holiday. Today was just another day to be hurried through.

Looking ahead for Bernard is unbearable. We have to decide, with our vet, Ana, the right moment to let him go; that precise time when his quality of life has diminished and before he is in significant pain. I also want to hold him in my arms at home as Ana puts him to sleep. The thought of that leaves me in tears.

The only way to handle what’s to come is to take one day at a time, as Bernard does. He has no thoughts of tomorrow. He lives for now. This morning, he jumped off our bed at 6.30am, was first out the door for a walk and came back and gobbled up his meat and biscuits breakfast in seconds.

He’ll spend his day by my feet as I work at my computer screen. He’ll follow me into the kitchen when I make a cup of tea and eat my lunch, hoping to catch my eye and get a tasty treat from the fridge. He receives one more often than not.

Still full of vim and vigour, he will rush through his evening walk into the woods and along the beach and back. He’ll wolf down his evening meal and follow our comings and goings all evening before settling down next to us on the sofa to watch television. Later, he’ll bound up the stairs to take his place at the end of our bed.

We do not know how much longer we have together. There are no outward tell-tale signs of liver failure yet. The liver is a tough and resilient organ. The progress of any cancer is hard to predict. We cannot tell if that “squashed orange” tumour took months or even years to grow to that size, nor how slow or rapid its future growth will be.

The liver can function even when it is 75-80% impaired. The healthy, cancer-free part of it can also regenerate itself. Bernard now eats a hepatic, liver-friendly diet mornings and evenings. He has liver supplements and tablets to help his liver process bile. We are doing all we can to make his time with us as long and as happy as we can.

So, today is a good day for Bernard and for us. Tomorrow may not be. It may be the beginning of the end. But we can enjoy what we have here and now. That’s the key to happiness, I think. It’s what my little dog Bernard has taught me and I’ll remember it for the rest of my life.