All best friends were strangers once. Why, then, does reaching out to someone you don’t know, making platonic connections in the modern world, feel like such a bold, even brave thing to do?

Let me tell you about my friend, Pauline. Like all good friends, we make a point of catching up at least once a week, talking for hours about everything and nothing at all. But Pauline and I, while always there for each other, are unlike more conventional companions because, as well as being born 50-odd years apart, and living several hundred miles from each other, we’ve never actually met. We’re telephone friends.

It was the peak of the Covid-19 pandemic and I was watching cat videos on YouTube. An advert popped up – an older-person charity seeking to combat social isolation through weekly telephone calls. Thirty minutes a week was the commitment. A simple chat could change an older person’s life, so they said.

There were rules, of course. You were only to speak on the phone, only to know each other’s first names, never to meet in real life.

Now I volunteer for several elderly charities, but back then I hadn’t given much thought to it. Yet the idea immediately appealed. Perhaps it was an age thing. I had just turned 30, a milestone no one can fail to ignore, and I was beginning to wonder what mark I was leaving on the world, what my future held, who I was. And then there was Covid, of course.

It’s no coincidence that this all started in 2020. Was it a sense of privilege I felt during the pandemic that drove me to sign up for these calls? Was I trying to cleanse my own conscience? A young man in a nice flat with a nice boyfriend, never going without food, or employment or, for that matter, company.

I’m sure I wasn’t the only one who found myself pondering those big existential questions during those difficult weeks, months (years, wasn’t it?).

It was around that time that I’d taken a break from my work in television to finish writing my novel, as indulgent as that sounds, and I had some time on my hands, to put it lightly. And so, after completing various vetting procedures, security checks and training programmes, the calls began.

“Do you watch a lot of television?” I ask.

“Of course!” Pauline answers. “I never have the telly off! It’s become a kind of friend. What do you watch?”

She’d beaten me to it. I’d built a mental crib sheet of shows I assumed she would watch in preparation for the call: Countryfile; Cash in the Attic; Countdown. I’d watched them all the previous week in case the conversation dried up.

“I watch reality TV.” Pauline announces. “I like Made in Chelsea.”

I spit my coffee out. “Really?”

“Of course. I watch it on E4. And that other one in Essex. Haven’t missed an ep of that.”

On paper it shouldn’t really work, of course. Our lives are poles apart. And yet, despite all our apparent differences, there is more that unites Pauline and me than divides us. Somehow it does work.

A few months in and there’s little we haven’t discussed. And not just what we’re watching on the telly, but memories from our past, dreams for our future. With every call we get to know each other a little better, become more comfortable revealing a little more of ourselves. But how sad, I think, that it took a national pandemic for this to happen. This friendship, and countless others across the country, would never have blossomed without it.

“My cat, Muriel,” I say, one day, “she turned five yesterday. We threw her a party. She tried some Pawsecco. It’s nettle and ginseng, lightly carbonated. I sound mad, don’t I?”

There is a moment’s pause. “It’s nice to hear you sounding more yourself,” she cuts in, out of nowhere. “Is it the tablets?”

“Sorry?”

“The tablets you told me about – are you feeling better? Happier?”

It was a few weeks earlier that I found myself divulging my mental health struggles to Pauline over the phone. I’m usually quite reluctant to talk about such things, even with my closest friends, but perhaps that’s one of the perks of a telephone friendship, not having to look another person in the eye.

“I think so,” I reply, tentatively, though I know it is true, I am feeling much more myself, but there is something about the fact that it is coming from Pauline that floors me somehow.

“I’m glad you’ve noticed, Pauline. I’m feeling much better. Thank you.”

There is a straightforwardness to our relationship, I realise, a connection deeper than I could have imagined when I first signed up for these calls. I guess sometimes in life we’re not sure what we’re looking for until it presents itself right under our eyes or, in my case, ears.

“I hope you don’t mind,” Pauline says, “but the other day I was talking to a man from the electricity board and I got on to you. I called you my friend. Is that OK?”

“Of course you’re my friend,” I reply, but it is only as I say the words that I realise it is true. I’d be lying if I said I didn’t take comfort in knowing that someone is there for me, as much as I am for them. Someone who is always at the other end of the phone. Real friendships aren’t transactional or philanthropic. They are mutually beneficial. Life enriching.

Pauline sighs deeply and I hear her shake her head. “If only I had more gays in my life.”

I start to laugh. She is forever extolling the virtues of homosexuals. “What do you mean?”

“Oh, I’ve always had an affinity with gay people. Men, and women.”

I smile into the phone.

“There’s another name for someone like you, Pauline.”

“There is?”

“Yes, and it rhymes with bag nag.”

There have been many moments that have been anything but sweet. Thinking about her situation one day, during one of our chats, I am overwhelmed by her confinement, the cruelty of it all, and a thought enters my head, one that I’ve yet to fully consider. What happens when Pauline is no longer with us? When I ring and there is no answer?

“Are you still there?”

“Sam?”

“Why are you crying?”

There is an ugly guttural cry that comes out of me that I can’t control. I grab the pillow I am leaning against and press my face into it, suppressing all the rage, the sadness, the shame of it all.

It is a sickness in our society, I think. Where older people are invisible and neighbours are nuisances and no one cares for anyone but themselves.

“Let’s talk about something a bit cheerier,” Pauline suggests, and suddenly it is her comforting me. “How’s Tom?”

At the mention of my partner, a smile appears on my face. I smile.

“He’s got a lovely accent, hasn’t he?”

“He has,” I reply. “Aren’t I lucky?”

The previous week she’d overheard Tom on the phone to his mum, while we sat together on the sofa.

“And am I allowed to say that there is something very attractive about an Irish accent?”

“You are,” I say. “And there is. It’s like butter, Pauline. You should hear the things he whispers in my ear.”

There is a naughty cackle down the phone. “I’m glad it’s not just me then.”

“What do you look like, Pauline? I’ve never seen you, have I? We only know each other’s voices.”

I regret the question immediately. In all the hundreds of hours we’ve been speaking, I had unconsciously painted an image of Pauline in my mind and I was reluctant to have that image shattered.

“I know what,” she says, “I’ll tell you what I used to look like.” I feel myself exhale.

“I had long blond hair, reddish blonde, really, and a heart-shaped face. Hazel eyes, a dainty little nose, and a cupid’s bow mouth. Everyone used to comment on my neck – it was long, like a swan’s. And I used to wear a lot of jewellery – no point now, of course.”

I beam into the receiver, closing my eyes to try to imagine her.

“I should let you get on,” I add, realising what a ridiculous thing it is to say.

“You will ring again when you get a moment?”

“I will! Why would I stop calling?”

This has gone beyond volunteering, I realise. It’s been almost four years. Hundreds of hours of conversation. Countless stories. Laughter. Secrets. And now tears. It’s no longer charity, if it ever was. We’re friends, simple as that. I will keep calling Pauline, of course I will. I will keep calling until she doesn’t pick up.

Pauline’s name has been changed for confidentiality. The Fellowship of Puzzlemakers by Samuel Burr (Orion Fiction, £14.99) is available from guardianbookshop.com for £13.19