Last week I welcomed a new arrival – a three-month-old chihuahua named Maggie. Yes, at my great age – 74 – I have brought home a bouncing, yapping bundle of fluff. She could not be more adorable. She answers to her name and comes when called – but most important is her effect on my other chihuahua, 18-month-old Minnie. They play together, argue over treats and teddies and leap on to my knee together. Minnie’s even trying to help with house training, encouraging Maggie to follow her out to the garden for a wee. Success is not yet guaranteed, but bending down to pick up any mess is not good for me. Minnie was in desperate need of a friend, because last month my two older chihuahuas died suddenly, one after the other.

First, Madge became suddenly critically ill. She had endured surgery to remove cataracts, but somehow contracted gastroenteritis. She died despite every effort to make her better. Only a week later Frieda, who was 20, fell over in the garden. The vet put her to sleep at home. Minnie and I have been heartbroken. She has been grieving every bit as much as I have. She’s lost her appetite, hasn’t enjoyed her walks and has had no interest in playing games. The whole house has felt sad.

New arrival Maggie with Jenni Murray's other chihuahua, 18-month-old Minnie. Many elderly people who lose a pet don’t feel able to get another, in case they die and leave it abandoned. But I’ve never thought it’s kind to keep only one dog. Minnie needed a friend. My son, the vet, was horrified when I told him two years ago that I was planning to buy Minnie. ‘Mum,’ he said, ‘are you out of your mind, buying a puppy at your age?’ To be frank, I had some sympathy for this viewpoint. He’s no fan of chihuahuas and must have worried that he’d be responsible for my animals if I were to die. And chihuahuas are quite likely to live for 20 years.

On the other hand, the wording of his warning could not have been more calculated to make me determined to go ahead. This time around, when I told him I was bringing Maggie home, he was surprisingly sympathetic. He knew just how upset Minnie and I had been at the loss of Madge and Frieda, so he accepted my decision, with one request: ‘Please Mum, hire a trainer to help teach her what she needs to know. No more worrying about stepping in a poo when I come to see you.’ I took the advice on board and now work with a trainer, Sallie.

Some wondered why I hadn’t looked for an older dog, perhaps a rescue, but I knew Minnie would be happiest with a pal near her own age and her breed. And I’m happy to report that since Maggie’s arrival, Minnie is her old cheerful self again. As for what will happen in the event of my death – I have a secret weapon: a wonderful charity called The Cinnamon Trust. It’s only thanks to them that I’ve dared to take on a second puppy.

Because should the worst happen and my demise comes sooner than I’d hope, the charity guarantees it will look after Minnie, Maggie – and Suu the cat. Cinnamon – celebrating its 40th anniversary after being founded by Averil Jarvis when she lost Cinnamon the corgi, her companion for 17 years – promises that animals that have lived together will be kept together and join a new loving family. I came across the charity a year ago, when I was facing the most anxious time of my life. I’d spent several weeks in hospital, then nearly two months in care homes, one in Dorset and one in London, hoping to fix my broken back.

I was finally getting ready to gather my pets and go home alone – to become as independent as the pain allowed. My biggest worry, I explained to a group of my fellow care home residents one evening, was how I was going to manage three dogs when I couldn’t even walk to the local park. ‘What you need,’ said one very elderly woman, ‘is The Cinnamon Trust.’ My companion was so crippled with arthritis that she couldn’t walk her dog so she had two volunteers who took him out every day – all for free.

The trust is run from Hale in Cornwall but has 20,000 volunteers across the country – all checked and trusted pet lovers. I called the office straight away and within days was put in contact with Lizzie, Sacha, Becky, Richard, Liron and Katie. They quickly grew to love my dogs and my dogs loved them. But their friendship has become important to me, too. It’s cheering for a woman who lives alone to have a broad smile at her front door on a wintry morning.

It’s often assumed that those of us in our 70s or beyond are too old to take in a pet. But for me it’s having busy, young pets that brings joy into my life. They make me feel youthful and needed. There are times, you know, when a long-serving journalist like me encounters news stories so frightening, cruel and depressing they make you doubt your trust in human nature. My experience with The Cinnamon Trust and my volunteers has restored that faith in me.