The other day, when I was out walking and thinking first thing in the morning, as I almost always do when the weather’s good, I was pondering on the usual random stuff. As I’ve finished a novel and I haven’t quite started to allow myself to think about the next one – I like to have some time where there’s just empty space and a few birds tweeting in my head – I was letting my thoughts run.

I remembered a friend talking about meeting up recently with their best friend, and having a great time.

And as usual, my irrepressible enquiring mind asked, ‘What’s a best friend?’ What makes them the best?

The simple answer is, they are the one you decide is your best friend. Simples.

But what makes them best?

I suppose our first best friend is often our Mum, as she is ‘there for us.’ She’s our rock, our comfort, the person we go to that we trust most.

When we were kids we had ‘best’ friends, and there was a kind of Venn diagram of our social group, from the in crowd to outsiders. Our best friend was a constant companion. Sometimes they stayed, sometimes they changed and became others, like a country dance.

So, unsurprisingly, when I asked people what makes a best friend, most of them said, ‘Someone I can trust with my problems.’

That didn’t feel like a fair deal. There has to be some reciprocity. Friends aren’t just counsellors. So I thought a bit harder. If we’ve known someone for a long time, they’ve probably seen our ups and downs, been with us as we’ve changed and grown. Through thick and thin, you might say. So do we have to know someone a long time for them to be our bezzie?

Quite possibly. Or not. There are the people we just click with. Those people are vibrant, spontaneous, great fun. They think like we do, they are our emotional and intellectual equals, perhaps. Or they are just a bloody good laugh. Mischief is a great quality in a friend. And it doesn’t matter how long we’ve known them.

Loyalty is an issue. Understanding what makes each other tick. Knowing when to butt in. When to butt out. When to come and go.

There’s the sharing stuff that binds us. We share books, clothes, time, food, opinions. We care about each other. We defend each other fiercely. I’d defend a friend even if they were wrong. Then I’d tell them. Or not, if it was a wiser choice. And I’d hope they’d do the same for me.Friends embrace difference.

There are friends we can’t help being emotional with. They can cry on our shoulders, laugh at silly things, serious things. We share books and films and music and days out. Days in. Just days. We are safe with them. They are safe with us.

So kindness and fair judgement come into the equation. We know our friends won’t judge us negatively when we get things wrong; they won’t talk behind our backs or hold our faults against us. They accept us and we accept them.

There are friends we can’t help hugging. Friends where physicality is easy, where conversation and turn taking is easy. Where being together is the most natural thing in the world. And when the going is tough, nothing changes.

We do kind things for each other. We bail each other out. We tell the truth, sometimes. And sometimes perhaps we decide it’s better not to. They are our first priority, not ourselves.

There are friends we don’t see in ages and then, after the first few minutes of catching up, it’s like we’ve never been apart.

There are all sorts of friends. People we see for any reason, whenever we can. People we meet for specific reasons because we share a bond, a common interest. People we work with and like a lot because they are great. Internet friends. People we’ve never met, but we like and respect everything we know about them.

Friendship is constantly being redefined.

But friends are people we forgive easily; we don’t hold grudges. We don’t expect each other to be perfect. Friendship is love, and love is given freely, without restraint.

I write about friendship a lot in my books. It’s the special bond of love between people who are similar or dissimilar, any age, any background, any sex. It’s the closeness between two people, or more than two people. Friendship is a gift we treasure and when we lose a friend, we have lost something uniquely precious.

And I suppose a best friend has all those qualities in abundance.

People and animals have a certain friendship. Which leaves me with a thought. If a dog is ‘man’s best friend’ then are we suggesting that a pet is more reliable than a human?

I don’t know. I’m a cat owner. Yes, they want constant food and cuddles and more than half the bed, and everything – absolutely everything – is on their terms. They’re perfect cats and companions, but they’re not perfect friends.

So, what about the best friend? I can’t choose between my wonderful friends – they are all best in their own way. And I don’t count their good points as being better or worse than those of another friend, because they are, in themselves, each the best. I love them all for who they are.

So it’ll soon be time to plan a new novel to write, with friendship at its core. And maybe love.

Ah. So – what constitutes the best lover?

All of the above in bucketloads? Is it friendship and more? Benefits? What benefits? And at what cost?

I’ll have to think about that one…