Sibling rivalry is alive and kicking – if you don’t squabble, are you even related?

A recent survey of 2,000 siblings concluded that a quarter of them still argued into adulthood. I am surprised it was only a quarter. The rest can’t be that close – I mean, if you don’t squabble, are you even siblings?

Parent-child relationships seem to be examined and discussed ad infinitum, sibling relationships less so – yet a sibling is another child, in your home, that you did not chose, who your parents seem hell bent on keeping.

The most important relationship in my life (after the ones I have with my children) is the one I have with my brother. He is older than me by just 16 months, and we still fall out from time to time over ridiculous things. I think it’s what keeps us young.

It’s never actually about the “ridiculous things” though, of course. Fall-outs rarely are. I passive-aggressively bought metal wine goblets for when he comes over because there is a significant reduction of my fancy glassware after a few visits from my bro: “Ha ha! You’re always breaking wine glasses so I got a metal one just for you! Hee hee!” – I joke, but actually what I’m saying is STOP RUINING MY STUFF!

I don’t really care about wine glasses, I don’t care if my other guests break one; but when my brother does, I am seven years old again and he has ripped the head off my Sindy doll and thrown it across our shared room.

Being the youngest child can bring back years of feeling powerless. If they break your things, all you can do is howl. They were walking when you were still a little slug, talking when you were babbling and their gigantic friends came to play – and all you are to them is their mate’s “little sister”.

Telling tales was no good in our house. My mum was the oldest of nine – six of them brothers – and had little time for me whining. If she saw us hit each other, she’d yell a farsi expression: “dasteh khar kootah!” (which, directly translated, means “the donkey’s hand is short” – baffling us and resolving nothing).

My brother and I were alternately best friends and worst enemies, interchanging between the two in a flash. We were pretty much left to it, as was the parenting style of the 1970s.

I don’t remember ever feeling jealous of my brother. I suppose he must have felt jealous of me at some point, because he was a toddler when I came along – and toddlers can barely share crayons without a turf war, let alone parents.

The two of us were glued together growing up (once, quite literally: a superglue experiment). We entertained each other – making up games, climbing trees and throwing tins of paint into fire.

Then came the inevitable rubicon of puberty where, once he crossed it ahead of me, the playing stopped and he gave me a silent “stay away from me now, see you on the other side”. This was a blow. Teenage years were a big splodge of “what is going on?!” and I was bewildered – especially as my brother, who had been the other half of me, now found me annoying and embarrassing and deeply unfashionable.

With the best will in the world, parents treat each child differently. My brother, like most older children, was given a lot more responsibility. The message to him was “look after your sister”, which he did, and does, and so of course I became the risk-taker; the one who went for a massive gambles in my career and my love life, because the message to me was “you do what you like because he will break your fall”.

The 2018 documentary Bros: After the Screaming Stops was the most sublimely raw and beautiful examination of a complex sibling relationship. Matt and Luke Goss, reunited professionally after 28 years, displayed all the love, tension and agony of what it’s like – as an adult – to reconnect with the kid who travelled beside you throughout your entire childhood.

They oscillate between respecting each other’s boundaries and clearly loving each other dearly, to unravelling and regressing to two 10-year-olds again, screaming “you shut up ... no you shut up” endlessly at each other and not being able to be in the same room.

I have dated a few men who are only children. Those without siblings can get quite freaked out by conflict in a relationship. They don’t understand why you’d be ranting and upset one minute, then wanting a cuddle the next.

Those of us who have grown up scrapping with the person we love best in the world do, though. Sibling relationships teach you that you that love and hate can live in the same breath.

I have always adored my big brother. I’d be lost without him – and I treasure him. But sometimes I still want to blow a massive raspberry in his face.