Mum, because she was more comfortable with the public-school ideal, got to decide which one. Her choice for the next five years was Gordonstoun. Maybe she thought that counting the queen as a fellow parent would prove to Granny and Granddad that she had not married as badly as they thought. It was a decision confirmed when she toured the other option – Roedean. ‘The girl who showed me round, would you believe, was barefoot!’

When I tell the story of those boarding years I moan about how I was dumped in the arse end of Scotland, completely on my own (Ed never counts). There was no one on my side. No one. Yet this is not strictly true. I had one unlikely sympathiser.

Ma Tait, who was one of the housemistresses. Some referred to her as Dinah. These names – the ‘Ma’ and the ‘Di’ – were how we tried to pick holes in her authority, and in our fear.

She was a small woman, thin and spiky, with short black hair and a voice that was easy to mimic. It had a posh grating quality, like the aunt in an Austen novel. Her own children had left home, and her husband too. She told me one Saturday afternoon that I did not need a man to get a lid off a jar. Just plenty of hot water.

Dinah drove her VW Scirocco fast, never giving anyone a lift. We watched her brake lights shrink ahead into the darkness, all of us hissing her off stage like a pantomime baddy.

One report reads that I do not concentrate, I am sulky, and I fool around. She uses the word ‘sheep’. I was. Some mornings I was ordered to wait outside the staff room during break. She would appear, cotton wool in one hand and make-up remover in the other, and scrub at my eyes herself.

So I repeated often and loudly, along with everyone else, that I hated her, but this was not the truth. Later she would give me a copy of Anita Brookner’s Hotel du Lac as a present, and pretend to overlook my persistent smoking behind the house. I was one of the few girls invited into her living room, where she made me tea and gave me cake. I suspect it was because she had glimpsed my world one Saturday afternoon in October 1981 and she never forgot it.

I had arrived at Gordonstoun with a brand new bike. A navy lady’s model that, looking back, Dad hoped would give me the status his poor Irish background couldn’t. It was a big deal and a ‘monumental’ expense.

An expense I parked in the bike shed. I had more important things to worry about. The new cohort of third-form girls were sorting themselves hierarchically, like grains of sand sliding through mesh. Within a fortnight my small self had been shaken down so far, the best I could hope for was that at breakfast the rest of them wouldn’t get up and move tables as soon as I sat down. Desperate to fit in with the bikeless I pretended I had none. It sat in the shed.

By half term when Dad arrived to pick me up, I was exhausted. I had waited all month, through every hour and every minute, for him to come rescue me. But instead of a tour of the dormitory he jogged round to the back of the house, and to the bike. I trotted after him, dread sitting in my stomach like stone. The last time I’d seen it, the seat and one rear mudguard were gone, its carcass being dismembered one piece at a time.

When he reached the gloom of the corrugated-iron shed, I held back, eyes closed. But nothing dimmed the crash, or his terrible wordlessness as he threw one mangled bike after another out onto the path. Tangled they fell, kicking up dust, my insides heavier and heavier, a need to pee coming on.

And then he was out on the path himself, the unrecognisable piece of junk that my bike had become aloft in his hand. It had been reduced, like me, to its frame.

I would be lying if I recounted the words he shouted. I wouldn’t even have remembered that same afternoon, my thoughts shrunk as they were to a white, hot panic. All I remember is the recognisable pitch of fury. Then his threat – he would be ‘taking it up with Mrs Tait’. I remember too that I ran after him, begging that he wouldn’t.

As we neared her door, Dad’s rage made it impossible to repeat my plea. Instead I dogged him across the grass in silence, the corpse of my bike swinging loose from his hand.

When he stomped through her back door he broke up a parent–teacher meeting. A flustered couple dusted themselves down as they blundered out onto the path. We heard him through the windows and the walls, the other parents stumbling over the gravel, looking back. His bellows about the bloody waste of money, the extortionate fees, the incompetence, could be heard right the way over to where more parents slid from their Range Rovers and Jaguars, every head turned towards the Tait kitchen door.

Then there was the crash of my bike hitting her Formica island. I glimpsed it through the window, squealing the length of the worktop.

Perhaps as Mrs Tait contemplated the rageful immaturity of the man in front of her, she spied me hopping one foot to another outside, my arms flapping so hard it looked as though I’d take off. Because soon the shouting broke off, and from within the kitchen there oozed one of those rich, heavy silences that scares a child shitless. It was the last time Dad ever visited me at school.