My little girl had to face the heartbreak of death - and I couldn't protect her from the overwhelming sadness

What an undervalued parental asset instinct is. We're so busy nowadays listening to supernannies and psychologists that we forget we have this secret superpower: our ability to know exactly what's right for our child whatever the experts may advise.

On Saturday evening I made a mum-decision purely on instinct. I made it in a split second and had no doubt it was the right one.

At around 7pm, Mr Candy rang from the vet's where our sick dog, Duke, had been for two days, his second stay in a month. The call was the one we were dreading and my husband wanted to know if we should let our eldest daughter make the heartbreaking trip to the surgery to say goodbye to the pet who had been her closest friend for most of her life.

Sky and Duke, the blind, diabetic Airedale (above), were an inseparable duo. Sky would lie on his less-than-fragrant dog bed, absent-mindedly stroking his ears while watching TV

For nearly 11 years, 13-year-old Sky and Duke, our now blind, diabetic Airedale, have been an inseparable duo, especially of an evening, when Sky would lie on his less-than-fragrant dog bed, absent-mindedly stroking his ears while watching TV. At teatime she would rest her feet on him as he lay under the table.

In his old age, she still coaxed him out on ever-so-slow walks, being his 'guide human', as we called it (blind dogs aren't as keen on walkies as sighted ones). She took turns with us to inject Duke twice daily with the insulin that kept him alive from the age of four.

The warm, furry calm of our giant dog was a huge comfort to her, much more so than to the other three children, aged 12, nine and four, who loved rather than worshipped him.

His journey from rebellious nutcase to canine OAP was never dull - Duke was endearing and high-maintenance. Three dog trainers brought him back, one after the other, when he was an unruly puppy, each shaking their head. 'I can make him sit,' one said proudly, 'but that's about it.'

Duke's lust for life (and food) knew no bounds. He was like a naughty fifth child until the diabetes began to take its toll.

Lorraine Candy said that she knew instinctively that her daughter would want one last hug with their dog, Duke. But when Sky cried after, Lorraine knew that she couldn't protect her from the pain (stock photo)

For a large dog with a severe illness, he's had a longer life than the vet forecast, and for that we're grateful. But that kind of logic doesn't make it any easier for your children at the end.

Sky is in that confusing space between childhood and adulthood, often overwhelmed with unpredictable hormones and new feelings. It's a tightrope to tread as a parent because you never know how they are going to respond. Everything about life is unfair in teen world and a hysterical reaction is always a heartbeat away. Burnt toast? Cue epic meltdown. Lost TV remote control? Cue inexplicable tears.

But even in our new world of out-of-proportion responses, I knew one thing instinctively about my smart daughter: she would want one last hug, one last nuzzle into Duke's fluffy neck and one last pat of his giant, bony head. I knew instinctively she would be able to cope with a goodbye.

So off she went with Dad while I stayed with our youngest, Mabel. My nine-year-old son was at a birthday party and my second daughter was on a sleepover. I would tell them when they returned, I decided. In Mabel's four-year-old world, death is an abstract concept, a bit like tomorrow and flushing the toilet.

'I am going to be all alone, aren't I?' she said when I'd explained about Duke. 'I'm the last one and you'll all die, leaving me in the lounge on my own.' Explaining the circle of life to Mabel was a welcome distraction, ending in a cup of tea and a biscuit. I am still able to make everything better in Mabel's eyes.

When Sky returned, red-eyed and clutching a plastic cup of water the kind vet had given her, she cried for hours until she fell asleep. I couldn't make it better. Overwhelming sadness had crept into her life and this time I couldn't protect her from it.

Lorraine Candy is editor-in-chief of Elle magazine.