Miranda Doyle’s father left his brain to science. Shocked by revelations about him after his death, she went to see the donated organ, in the hope it would somehow shed light on his deceit

I make the decision that I must see what is left of my father. His brain lies in Glasgow’s Southern General hospital, donated to the team who work on glioblastoma multiforme, a devastating cancer that has a survival rate of 15 months at best. Offered a place on a treatment study, he took it, and without being asked, bequeathed to the scientists who ran the trial, what was most useful to them. His organ of self.

Dad liked to do the right thing. This was the right thing, and a final act that was totally in keeping with the story we liked to tell ourselves.

Born into a home where hunger was the everyday, he hated the idea that anyone else should go without food. I would find him at the foot of Tottenham Court Road in central London with bags full of burgers, foisting them on to the forgotten homeless, although they would have dearly preferred the cash.

He had spent his Irish immigrant childhood begging from grocery shops near Edinburgh’s dockyards. His mother had fingered him as the best child she had for the job. Her sixth-born was a gorgeous combination of shame and pride, impossible to refuse. Each time he reached the till to utter the inevitable line, “but we’re starving”, he must have dreamed that when he grew up he would have everything he wanted. Everything. The storybook hero made good, and as a hero he was convincing. The spitting image of Clint Eastwood, he was also taut with that seething rage Eastwood is so good at. Bluntly, he scared many of us shitless.

I was his biggest fan. His pseudo mistress. Together we did the bitching about the wife, and the long telephone conversations most days. A heady combination of his heroic good-doing, together with my mother’s Christian bent were foils for his routine adultery. I was credulous. Completely sold to the story, and to the idea that there was no other woman he loved better than me. Mum was no contest and, on that, both Dad and I agreed.

A disloyalty that since his death is biting. Mum has found the courage for revenge. Now that he is dead, his consummate philandering leaks from her one woman at a time. Not to mention the two doses of the clap. I am furious. Furious with myself for my idiocy. God, it was always so bloody hard to feel angry with him.

So it is rage that brings me here to the Southern General. I need to see the organ of his deceit, and the tumour that destroyed him, weaving insidiously through the folds of cortex above his left ear. I have no idea what I am doing, but I am compelled to do something. I want to see what it was that enmeshed with his synapses, a cancer flowering like lies. A duplicity that is dismantling any idea of who he was.

Professor Greig, who cut his brain from its stem, has asked me to go straight up to the neuropathology department on the fifth floor. The lift opens on to scarred double doors and a damp smell of wooden benches. Greig gets up to shake my hand. In his office we sit down, and I say: “Where does it live?” The question is out of me before I can think of something more sensible to ask.

Facebook Twitter Pinterest Miranda Doyle with her father. Photograph: Courtesy Miranda Doyle

The professor rises from his chair and walks across the corridor to another room. He returns with a shallow empty bucket in white. “We store our donations in these.”

The consistency of the brain is like jelly, he tells me, and difficult to work with. It was in a larger bucket that the material, as he calls it, was “fixed”. Once the wet tissue was hard, what was left of my father was cut into 14 pieces.

He leans over and points out a book lying open next to me on the desk.

I look. The photograph is black and white, and shows a full brain sliced and arranged, left to right. Perhaps, I think, it will be less gruesome to view in pieces than as a bulk of creases and folds, recognisable as a brain. And as something that was once his. In my anxiety at what must come, I tear on.

“I wondered why his testes were not examined in the autopsy,” I tell the professor. “I wondered whether it was a kind of man-to-man thing, that you left this part of him alone as a mark of respect.”

Professor Greig looks at me blankly.

This fact has been bugging me for at least a week. Another pathologist will later explain that the testes might have been omitted from a full autopsy because they’re a bit of a “faff”. Usually they need to be poked up into the stomach cavity, and if tissue is “retained”, or “lost”, a golf ball is thought to make a decent replacement.

I repeat the question.

“The postmortem report states that the testes were not examined,” he says. It is the only moment that afternoon when he looks flustered, reaching over his desk for the postmortem report. Carefully, he turns the page and apologises. It is an oversight, he says, asking if I am worried that the cancer had spread.

“No, I am not worried about the cancer,” I tell him. “It was only that it seemed a glaring omission.”

“Excuse me?”

I say my father was unfaithful to my mother the whole of their married lives. And what has infuriated me the most, and is so bloody typical, is how his testes have defied that damning autopsy label which defined each of his other organs – “unremarkable”.

“Will I be able to take it home?” I ask.

“The donation?”

“I was thinking of a sea burial.” The Ireland question had come up a number of times. Turfing his remains into the Irish Sea from a ferry feels appropriate.

Professor Greig tells me there is a daunting amount of paperwork just for it to leave the building. Brains have the consistency of Semtex, he says: “You wouldn’t get it past security.”

Closing the report, he tells me that the viewing of the remains has been arranged downstairs in the mortuary chapel. In the lift, once the doors have concertinaed closed, he says cheerily to another doctor: “This young lady has come to discuss a donation her family have made to the department.”

The man colours and the exchange gives me the feeling that, in all his years as a pathologist – and he is due for retirement in a month – Professor Greig has never experienced a mission like this.

At the mortuary we ring the bell. A shadow hobbles into view. Mr Stewart, the mortician, has a stick. Professor Greig tells me that Mr Stewart has hurt his back and Mr Stewart, in white coat and blue scrubs, nods.

We enter the chapel, and again Professor Greig tells me that I may not want to see it. But there is nothing that would make me turn back now.

Mr Stewart opens the door to the viewing chamber. There is a small room: no chairs, a glass panel in one wall. The window is curtained. Behind it appears a hospital trolley-bed pushed up beneath the glass. Covered in white linen, it carries the brain.

Facebook Twitter Pinterest Miranda Doyle with her parents and siblings. Photograph: Courtesy Miranda Doyle

The sections are placed in three rows on a white tray. Dad’s label is soaked and almost unreadable with its autopsy name, number and place of death: “Doyle AO30139: Ayrshire hospice.”

The grey and white matter are in two diabolical shades of beige, the fan of nerve endings clear as the roots of a tree. The slices increase in size from the prefrontal section through to the diced gristle of the brain stem. The seventh slice has a small hole, the eighth an even larger one, while the ninth and 10th show ragged edges. The cavity is enormous.

The men wait for me to speak. It is impossible to imagine that this is him. This, in some essential way, is who Dad was, and who he pretended he wasn’t.

I start to ask questions about the cavity and the discoloration, but I no longer care what the answers are.

I realise I should emulate Professor Greig. As part of his “unremarkable” autopsy he has retained sections of healthy tissue to store alongside what was diseased. He has remained impartial in the face of a rampant brain tumour.

He has accepted my father as he was.

• A Book of Untruths by Miranda Doyle is published this month by Faber & Faber, £14.99. To order a copy for £12.74, go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p on orders of more than £10, online only. Phone orders min p&p of £1.99.