She opens her sermon with a dig at the school chaplain, which calms her nerves and captures the children’s attention. Then, in a powerful upper-class voice deepened by chain-smoking, she describes how, while Britain was indulging in VE Day celebrations, she was on her way to Tuzla, where 32 of “her” children had just been blown up in a mortar attack. “Evil will triumph,” she growls, “if good men do nothing.”

Trench is unable to do nothing. While most of us languish in a state of compassion fatigue, she has been driven from an early age by a kind of compassion addiction. Single-handed – she is not a person to take orders – she has tackled homelessness, alcoholism, drug-addiction, del-inquency, crime and, most recently, war. Three years ago, at the age of 47, she started constructing a series of subterranean schools behind the front line in Bosnia and, though not exactly a traditional Papist, has been voted Catholic Woman of the Year for her work there. “I have often been told to fuck off and mind my own business, but I won’t,” she says, with a wide, appealing smile.

“Suffering is my business.”
So used is she, in fact, to being with the downtrodden and distressed that, as someone not in obvious need of help, I felt myself the object of suspicion. Despite a big-hearted welcome – she lit the fire as soon as I arrived and produced an enormous dinner – she seemed uneasy. “You are so bloody well-balanced,” she told me, not once but four times It was not a compliment, nor did it seem wise to retaliate. Sally Trench’s experiences in Bosnia have taken their toll – her face is grey and strained, her complexion papery, and behind her brash exterior one senses a person of such brittleness and complex insecurity that to upset her might be dangerous.We met at her home in Wendlebury, the Oxfordshire village where she has lived for four years. Her house is unpretentious but large – upstairs are 10 bedrooms, one of which she has converted into an oratory – and she shares it with an ex-headmaster, an ex-convict and an unemployed Oxford graduate The garden she has given over to a youth centre. “Nathan!” she yells abruptly, striding to the window to catch the attention of a lanky adolescent loafing down her drive.

“If you buggers haven’t cleared up your fag ends by 11am tomorrow, I’ll kill you.”When she moved to Wendlebury, Trench’s plan was to make her house a base from which to help gifted delinquent adolescents take A-levels Then, in spring 1992, war broke out in Bosnia. “Like the rest of the world,” she says, “I sat watching my television set and was horrified by what I saw. I thought, ‘Hell! I can’t sit here in my comfortable home and do nothing about this. I must get out there!’ “Though she had never met him, she decided that Richard Branson was the man to help. “I knew a letter to him would never get through his secretaries, so I composed a letter to his wife.

‘Dear Mrs Branson,’ I wrote, ‘As a mother of four, I am sure you are as worried as I am at what is happening in Bosnia. I have no money and your husband has a plane, and I want to go to Split.’ ” A fortnight later, the flight was fixed.In Bosnia, she worked her way around the refugee camps. “It was,” she says, “the first time I had really looked evil in the face. When you’re working with drug addicts or meths drinkers, however much empathy you feel, you can’t help but think, ‘Come on, it’s your own bloody fault.’ But these were totally innocent victims.