When, as a teenager, I began to show an interest in the fine two-manual Hilsdon organ in St John's, my grandfather was over the moon and bought me a set of new hymn books and various manuals to help me teach myself the basics. I soon began playing for the liturgies there. This, combined with my school studies in choral music from all ages, meant that my interest and love of sacred music took off in a big way, which was to have implications for the rest of my life.

Working-class Ayrshire is a hard-man's paradise, but could be purgatory for everyone else. The way people like my grandfather survived was to put on a hard skin and hide his true self underneath. He was good at it. He had to be. His own father was an abusive drunk who could make life misery for his family. When his sons reached a certain age, they worked out that if they kicked him in a specific place, they could dislocate his leg and render him harmless on the floor for a few hours, as he raged in his drunken stupor, thus safeguarding mother and children from physical abuse.

On another occasion as a young man, my grandfather was having a drink with friends in a local bar after work. A stranger approached them and announced that my grandfather "had the map of Ireland written all over his face." A poetic observation perhaps, but in sectarian-infested Ayrshire one did not hang around to explore metaphorical subtleties. Turning the other cheek, they headed for the door to avoid any escalation, except for one, who couldn't quite contain all that pent-up male rage. At the door, my grandfather turned to see his friend throttling the living daylights out of the mouthy poetic figure, who had chanced his arm with them, an inch too far, apparently. He rushed back in to extricate his   fury-infused pal from an increasingly sticky situation before the local "Loyal Defence League" turned up.

It may have been as part of a determined flight from these blood-boiling belligerencies that my grandfather sought solace in music. He may have been dour and authoritarian, but he loved his family and they loved him back. I felt especially nurtured by his encouragement. Just before he died he confided in me a truly remarkable revelation of the power and presence of God which involved a piece of my music. It will remain our secret, but what stunned me most were the words he used. He did not normally waste words. He had a working man's suspicion of pretension and fancy, and yet here he was, hours from death, trawling deep into his heart and memory to show me that music brings you into the very immanence of a loving God. No learned tome on theology or musicological philosophy has explained this reality to me more clearly since.

George Loy's eldest daughter, Ellen, my mum, married James MacMillan senior in 1958. In his way too, he can seem strangely out of place. He doesn't drink (much), and is quiet, thoughtful and sensitive. He prefers the company of his family to that of hard-drinking men. One of my earliest memories of him is observing him on his knees before a statue of Mary, lost in a distant humble introspection. Snatched moments like these showed me more about being a man than any of the other masculine madness surrounding me at the time. My dad's own work as a carpenter seemed another world away from my chosen path in life. And yet I was always struck, and impressed, at how much care he took in the making of things. There were strict techniques to his craft which had taken a lifetime to learn. Again there was no place for fanciful self-indulgences in the manipulation of wood and lathe. I may use different tools and materials from my dad, but he will never really know just how much of an influence he has had on me.