I became a bit of a tearaway. Growing up in Finglas in north Dublin was tough so, to "fit in", one had to accept the responsibility of a little petty crime from time to time.
I could drive by the time I was eight and ours was the first call neighbours made if they happened to be locked out of their car or house.
But I never stole a car or burgled a home in my life. However, like all children then, I was partial to a little shoplifting.
[When he was almost 10, a new supermarket opened in Finglas and Brendan, with a couple of pals, decided to check it out.]
I was caught - you always are - and I had on me a roll of Sellotape and a bicycle lock.
I had nothing to stick, nor did I have a bike, so don't ask me why I lifted them, I have no idea. They were there.
Yet, the court case could have been avoided. My mammy had enough pull to get it overlooked and for the store to accept an apology.
But she had a different thought. She knew that the crime was so petty that I would only be scolded by the judge and given the benefit of the Probation Act.
And she truly believed the day in court would frighten the daylights out of me and deter any future crimes. It was a good plan.
But what she had not figured into the equation was a judge whose appointment she had objected to. I was sent down. Three months in a reform school in County Laois.
It was a strange day. We left the courtroom that morning, Mammy smiling. Outside I asked her what had happened.
She brushed the question off with a "Don't worry about it," so we headed for the bus into town to celebrate my birthday.
What an amazing day we had. We laughed and laughed that day. I was always able to make Mammy laugh heartily and nothing ever gave me more pleasure.
In Bewley's, they would normally bring to the table a three-tiered plate that had on it two cream slices, two cream buns, two cream puffs, and two chocolate éclairs.
But not today. I saw Mammy whisper something to the waitress, the woman smiled and the plate arrived with eight chocolate éclairs on it.
I can still see the picture in my mind, the waitresses in their black uniforms with white lace headdress and aprons, standing in a circle singing "Happy Birthday, dear Brendan" and before me just éclairs.
Mammy prompted me on until I had eaten every one of the eight. No problem. Mammy howled with laughter.
We arrived home that evening exhausted. Mammy dropped into her armchair and I ran a basin full of hot water and added some Epsom salts to it.
I carried it in and laid it in front of her.
Then I pulled off her suede boots and placed her feet into the footbath. She rolled her eyes and giggled with pleasure. I sat on the footstool just smiling at her.
"Thanks Mammy. That was the best day of my life," I said, and meant it. She sat up and leaned over to stroke my cheek.
"I'm afraid it goes downhill from here Brendan," and I could hear the seriousness in her voice.
At nine o'clock the next morning, I stood outside Pearse Street Police Station.
My brother Finbar had accompanied me to the door but he wouldn't come in. I had a pair of trousers, three pairs of jockeys, three T-shirts and three pair of socks packed into the only bag that was available in the house. A pink weekend case.
I was taken by police car to the place of incarceration and shown into a dormitory full of beds.
I cannot begin to tell you how frightened I was. After putting my clothes away and hiding the weekend case, I was taken to the office where I was allowed to call my mother and let her know I had arrived safely.
ACTUALLY, this was seen as a novelty by the Christian Brothers who ran this place. They had never had a boy in there whose family had a phone.
"Are you okay?" Mammy asked. She sounded sadder than I was.
"I'm frightened Mammy."
There was a pause. "You have nothing to fear there, Brendan. Nothing."
She was so positive this was the case that I believed her and, I swear it, there and then my fear just dissipated.
When the call was done, the Brother began to question me. "Do you attend Mass, son?"
"Are you frightened, son? About being here?"
"No Brother, not now." Then I explained. "Me mammy said there was nothing for me to fear here."
"Your mammy is wrong, boy," he said dismissively.
"No, Brother. She's not. Mammy is never wrong."
He just smiled. I received a letter from Mammy every day I was there. But I wasn't there for the three months demanded. I was out in three weeks.
Mammy pulled every string she could and got me out. I never found out how.
Tears streamed from my face as I ran across the football pitch to the dorm to pack. I was going home.
I had learned my lesson. I vowed there and then never ever again to get caught.
I would never put myself in that sort of position again.
And the lesson according to my mother? "If you do something and it turns out good, you stand on the rooftops, and you tell the world. But you've got to do the same if it goes pear-shaped."
n Adapted by Brian Beacom from The Real Mrs Brown, Hodder & Staughton, out now, £20