The scene is the main doorway of St Paul's Cathedral, London.

The date is September 30, 1980. A tramp is seeking access to the Cathedral. He is turned away because, says the usher, an “important service” is about to begin – two bishops are to be consecrated.

“I know,” says the dosser. “I’m the preacher.”

Father Roland Walls was an extraordinary man. He was easily mistaken for a down-and-out. Something of a mentor for me, he was a joyfully irreverent man of God. His death on Thursday at the age of 93 leaves a void.

I first met Roland when I was a student for the ministry at New College, Edinburgh, where he was a lecturer. Some of us gave him a hard time. We repeatedly pressed him to justify his theological starting point. Roland enjoyed these robust exchanges; a first-class honours graduate of Cambridge University and a Fellow of Corpus Christi College, he could give better than he got. Even as we struggled with him we loved him; we enjoyed his mischievous hilarity as he talked about the surreality of dressed-up church leaders pontificating weightily on matters of church and state. Possessed of a highly developed sense of the absurd, he was focused on the heart of the matter – the Gospel of Christ – and hung loose to all the rest.

His was an astonishing journey. In 1962, when a priest was needed for Rosslyn Chapel, near Edinburgh – yes, the Da Vinci Code place – his friend, Bishop Kenneth Carey, invited him to take charge. When Roland demurred, Carey told him: “I’ve offered it to three dozen people before you, and this is scraping the bottom of the barrel!”. Carey clearly knew his man. Still uncertain, Roland took a train journey north. He noticed a big sign on the back of a coal train, which said, “Return Empty to Scotland”. Game on.

Within a few months, Roland had moved out of the chapel parsonage and had, with friends, bought the old Miners’ Institute in Roslin village. It became home for a small community marked by contemplative prayer and service. Roland lived in a hut in the garden. Its presence became known by word of mouth, and increasing numbers of people beat a path to the door of the ramshackle premises of the Community of the Transfiguration. If you turned up for a bowl of soup you could find yourself sitting next to a professor of theology and a recently-released prisoner. People made their way there for spiritual counsel, for vocational direction, or simply to cry about the state of their lives.

Roslin – thanks particularly to the self-giving lives of Roland Walls, Brother John Halsey, and Sister Patty Burgess – became a place of healing.

In 1981, with the support of his community, Roland converted to Roman Catholicism. He said he did so “as a sign of contradiction”: true ecumenism, he felt, needed to have at its heart the pain of separation.

His friend, Professor Henry Chadwick, called him “a mole under the fence” –a description which Roland relished. The monk became a Catholic priest two years later.

I know so many people, Protestant and Catholic, who have been influenced by the Roslin community. I felt that something of the wisdom of Father Walls needed to be captured before he died, especially in his favoured conversational mode. So I recorded a number of conversations with him on topics such as faith, vocation, silence and justice, as did Dr Mark Chater; they were published by Saint Andrew Press under the title Mole Under the Fence. Another person influenced by Roland, Archbishop Rowan Williams, wrote a preface.

The funeral Requiem will be held on Friday at St Mary’s Roman Catholic Cathedral, Edinburgh, at 11am, followed by burial at Roslin.

I hope that no down-and-out is turned away, and that holy mayhem breaks out at the funeral. After all, hilarity is a sign of the Resurrection in the world of Roland Walls.