The Archbishop of Canterbury spoke powerfully today of how faith in Jesus Christ had given him "certainty" after a childhood punctuated by hunger, acrimony and his parents' divorce. He also spoke of how faith and prayer helped him deal with scenes of horror, such as the grave of a mass murder he witnessed recently in South Sudan.

Speaking to Kirsty Young on BBC Radio 4's Desert Island Discs, he admitted that he had found that time spent doing the ironing was a good time to pray to God.

When in London or at Canterbury, morning prayer, evening prayer and midday communion were "really really important", he said. When in a parish, he had found he was not praying enough. At the same time, with a young family of five, the ironing would build up. "I found out that you can iron without thinking too much and without falling asleep. So I discovered that you can pray and that the quality of ironing does not suffer too much."

In his present job, heading a worldwide communion of 77 million people as well as the southern province of the Church of England and the Canterbury diocese, he said that it was not possible to do too much praying.

It was also revealed last week that he recently became the first ever Archbishop of Canterbury to attend the National Security Council, chaired by the Prime Minister, to discuss current intelligence and security issues. It is understood his views were sought on the jihadist terror group Boko Haram in Nigeria, of which he has some knowledge from his time in the Niger Delta while he was a canon at Coventry Cathedral.

Welby, who was in the BBC studio just hours after flying home from a visit to Sierra Leone, was ordained priest in 1993, just 19 years before his translation from Durham to Canterbury.

He gave a moving account of a childhood punctuated by hunger and his parents' divorce. One early Christmas was spent staring hungrily out of the window as his father lay in bed all day.

He admitted he loves music but finds he is "incapable" of remembering it and his staff helped him choose the discs for the programme.

His first record, In The Jungle, reminded him of playing the card game Racing Demon with the family, when he would try to put everyone off by singing it.

Alongside these happy memories, Welby also described how he deals with scenes of horror, such as witnessing graves full of mass murder victims in places such as South Sudan. "That is a classic area of silent prayer, holding this scene before God with him yourself and the scene."

Asked why gay relationships seen as inferior in church's eyes, he said he could not answer the question "very well" because the local and global church were now engaged in talks about it. He had just visited all the provinces and this issue was seen as part of "total obedience to Christ", either in favour or against. People were "passionate" about it and on either side, believed their view was part of what made the Church "holy". It would be "inappropriate" for him to "weigh in" now. He admitted it looked impossible to keep the Anglican Communion together.

He chose one piece by Beethoven because it brought back memories of his grandmother's house in Norfolk, where he learned to sail, and enjoyed a sense of security, safety and a place that was good. He also chose a Tavener piece for its message of breaking out of the darkness. "If you are doing reconciliation work there is a lot of darkness about."

Welby was a honeymoon, baby born in 1956, and his parents divorced when he only three years old. His earliest memory is from 1961, when his mother took him for tea with her former boss, Winston Churchill. "I knew it was important and I couldn't remember why. He cried and I don't know why. And because he cried, I cried too. And then we had tea. My mother later told me he cried a lot."

At about the age of 12 he noticed his father had alcohol problems. As he grew up, his father's behaviour was always unpredictable, "sometimes full of rage and anger and expressing that loudly." He had legal custody and Welby spent a lot of time in his care, although he remembers his parents arguing often about it. "It felt very painful at the time but I didn't know anything else."

One Christmas, his father spent the entire day in bed. "That was a grim grim day." He went out once or twice, but everything was closed. He "scrounged around" in the fridge for something to eat.

The young Welby was not without connections, however, and was sent to Eton, where where he went to chapel twice a day, but remembered little of it except the Head Master falling out of the pulpit once.

In spite of low A level grades, he got into Trinity College, Cambridge. "In those days you got a second chance." The fact that his father was going through a bad patch might have had an impact but mainly he put his head down and studied. He "loved it", met his wife Caroline there, and rowed on the river. Welby admitted he had a competitive edge but said he tried not to let it get out of hand, "unsuccessfully".

The seed for his conversion was planted when, between school and university, he was teaching in Kenya and shared a house with a committed Christian. It had an impact, and although he initially ran away from it, in his second year at Cambridge a friend explained how on the cross, Jesus died and that meant in "an extraordinary way" that "I could know God." It made sense to him. He prayed, "and Christ came into my life."

The Archbishop spoke of the tragic death of their first child, Joanna, in hospital five days a car crash on the way back to the UK from Paris. "It's just the constant reminder of the uncertainty in life. The only certainty in life is Christ." He was asked in Sierra Leone: "Why Ebola? Why is this happening?" He said on the programme that he never gave answers to this question, except to point to Christ who died on the Cross, unknown and unfairly. He added that the most helpful thing, when dealing with incidents such as the anniversary of his daughter's death, was to celebrate with love, and remember what they gave each other. "In other words, attack the day so it doesn't attack you."

In 1989 he chose to leave the oil industry. He could not escape sense that God was calling him but had loved his work, so he was dragged into the Church "kicking and screaming". He felt now a "totally" different man. "Being a clergyman is a process of being trained by the churches in which you work. I've had very good trainers." Through the life of those churches he had been directed, trained and "transformed" by the spirit at work.

Welby admitted that the Church could come a cropper and did so especially if it tried to come across as "holier than thou", such as over the Wonga issue, where he had criticised the company's practices before discovering the Church itself had a stake in it. But he said he could not deal with people without being aware of his own sin and own failings.

He did not put himself forward to be Archbishop. He said: "We were all told to write a proposal". He described "imposter syndrome" as a "constant companion", and described how he had said at the time that it would be a "joke" if he was appointed. He also spoke about the importance of sharing his faith. "Evangelism is a churchy word for seeking to share the good news of Jesus Christ with people."

Speaking about atrocities in war and terror, he said what humanity was capable of always shocked him, "not just in the name of religion". Religion was "a very good hook on which" to hang things on. While it was important to be "realistic" about the failures of the Church, it was also vital trust in the love and truth of Christ.

His job had encouraged "remorseless teasing" from his family, along with their habit of reminding him how fallible he is. On the desert island, he said would survive with prayer and reading the Bible. His last choice of music was Benjamin Brittan's War Requieum, written written for the consecration of Coventry's new cathedral, and which draws on the poetry of Wilfred Owen. "It's my favourite bit of music in the world." His luxury item was the entire seven series of The West Wing.

The broadcast led to #desertislanddiscs trending on Twitter. Mark Russell, Christian Tweeter of the Year in 2013 and 2014, tweeted three times, including:

His daughter Katharine also joined in ‏@kwelbyroberts:

TV celebrity Fern Britton ‏@Fern_Britton also tweeted: