President's pastor on a mission

Scriptwriters salivate about life stories like Alfredo Cooper's. To be fair, there aren't that many lives to match his: from working as a postman to rubbing shoulders with presidents.

Despite attending the Oratory School in Woodcote, Reading, founded by Cardinal Newman, the 62-year-old spent his formative years as a "good honest atheist" who could never see himself as a Christian. His conversion came while studying Spanish and French at Bristol University – the beginning of a spiritual journey that culminated in his role as chaplain to the Chilean president Sebastian Pinera and leading the nation in prayer while "Los 33" were trapped for 69 days after the 2010 Copiapo mining accident. This month he is back in the UK doing missionary work.

"I crusaded against faith at school," he said, "and used to think Christians were escapists. I had a very good French master, Mr Wood, who challenged us on faith and encouraged us to question things, so I did." But three years of study and new student experiences turned him from a "Marxist materialist" on entering university into a committed Christian when he left, determined to spend the rest of his life doing God's work.

His "road to Damascus" moment was not conventional. "I got a group of atheists together and we held a seance, and while not converted overnight, something happened that day and it unlocked a religious part of my brain. It shook my materialism and I moved from hedonism and drugs into a New Age spirituality. I had a sense of a person with me and that person was Jesus of Nazareth. I thought I had gone mad."

After graduation and a temporary job as a postman, Rev Cooper taught in Montserrat for a year before returning to England to train at All Nations Christian College in Hertfordshire from 1972 to 1974. Rev Cooper, who is fourth-generation Anglo-Chilean, returned home to Santiago and found a nation in turmoil after General Pinochet seized power in a 1973.

"There was a sense a new Chile had to emerge from the horror. We aimed at reconciliation on both sides and a lot of my work took me into prisons to speak to political prisoners, many of whom left to live in England because of the links our countries have. All the torture hurt Chile, and it has taken many years for the reconciliation process, very much led by the church, to happen. We still have some way to go."

Rev Cooper's focus these days is often on dealing with social unrest among indigenous Indians and arguments over land rights. The growth of his Trinidad church in Santiago did not go unnoticed in recent years, and in 2009 he received a call from an aide of Mr Pinera's, saying the President wanted to meet him.

"I went to see him and he asked me if I wanted to become his Protestant chaplain. Now my job is to provide support and prayer for ministers when they need it." And they needed it later when the Copiapo mining accident happened in 2010. The world watched for 69 days hoping that "Los 33" made it out alive. "I held a prayer meeting for the cabinet and it soon turned into a national prayer meeting because it was televised. The first night the men were trapped, they all went down on their knees and prayed to God to get them out."

After it became clear the mining company did not have the resources to cope, a massive international rescue effort succeeded in lifting the miners to safety. Rev Cooper called it "a miracle". "These guys survived on half a teaspoon of tuna a day. We all rejoiced when the second drill worked and pulled them out."

A movie remains in the pipeline but remains delayed due "legal wranglings here and there".

During an official visit to Chile in 2011, Barack Obama recognised Rev Cooper from the latter's visit to Washington earlier that year at a White House prayer breakfast. He had acted as translator to a rescued miner, Jose Henriquez. A photo soon emerged of the pastor with Mr Obama and Mr Pinera beaming either side of him. "People thought I had broken strict protocol by asking for a picture, but it was President Obama who wanted his picture taken with me! It felt proud to be with two heads of state who believe in public prayer."

Spreading the word has proved fruitful in South America and he hopes to "light up the cooler climates of Christianity in the UK" as he spoke from Cookham, Berkshire, halfway through a missionary visit to his ancestral home in his role as partner of the Church Mission Society. "People I meet are very appreciative about the way faith is growing in Chile. We're on a roll over there. There seems to be a deep anxiety here about spirituality, so now we're encouraging Britons to find their faith."