When Russell Muir talks to school students about God, he usually takes three props with him: a starting-pistol, a box of doughnuts and a necklace. He starts with a competition to find the tastiest doughnut - and the brand with the most jam always wins. He then asks a volunteer to place an apple on their head. After a few cracks about his dodgy eyesight he whips out his pistol and aims it at the apple, to inevitable gasps of horror. If he is feeling laddish, he replaces the crucifix hanging from his neck with a mini gallows and invites the audience to admire his jewellery.

Russell’s props have a serious message: we may muddle through without religious faith, but with holy jam to fill the God-shaped void in our lives, we will do better; if we trust in God, it will also help us avoid life’s pitfalls and, thirdly, why recoil from wearing one instrument of execution as decoration, yet happily wear another?

Russell has spent several years as a schools worker with Youth for Christ (YFC), a charity founded in 1946 in Birmingham by the American preacher Billy Graham. The organisation now runs 50 centres throughout Britain, with 70 per cent of its work aimed at schoolchildren.

Trained staff manage teams of volunteers, usually people in their twenties, who take assemblies and PSHE and RE lessons for all year groups. Martin Stand, YFC communications officer, says: “They are there to meet people where they are, by taking a holistic approach to religious education, and to help children feel better about themselves, with a Christian perspective.”

Marriage, drugs and abortion are among the subjects up for discussion, alongside more traditional RE fare, such as the meaning of Christmas and Easter. Typically, a group of YFC volunteers will spend a week in one school, oganising discos and sports competitions in addition to lessons and, when asked, helping with teenage angst about relationships, acne, or exams.

Steve Hawkes, 20, a YFC volunteer in Staffordshire, says that sex is often an issue. Questions such as, “If you’re a Christian, can you have sex?” are often asked. He stresses the importance of not being judgmental. “I explain that sexuality also involves our spiritual and emotional selves, because many of them do not know what intimacy means,” he says.

Steve Wright, head of RE at Four Dwellings high school in Quinton, near Birmingham, invites the YFC drama group, Activate, into school every July. He says his pupils always want more. “YFC are truly professional. They understand the kids’ pop, sport and fashion - there’s no cringe factor - and they get the kids thinking and talking,” he says.

Janet King, a former RE teacher and now RE consultant to the London boroughs of Newham and Thurrock, likes the way YFC volunteers convey their message in a way that is enjoyable and acceptable to children who have little or no religious teaching or experience at home.

But it isn’t all fun. Three days after the Dunblane massacre, Russell Muir gave a talk in a comprehensive school in Harlow, Essex. Aware that pupils’ questions would reflect the seriousness of the tragedy, he left his pistol and gallows at home. His young audience all wanted to know: “If there is a God, why did it happen?” “I couldn’t say that God would make everything all right,” he says, “because life’s not like that. What I did say was simply, ‘I don’t know, but I do believe that there is a God, that he loved those children, that God allows us to make our own decisions and that here, someone made a bad decision’. That may not have been the answer they wanted, but it got them thinking.”

Youth for Christ, tel: 0121 550 8055. www.yfc.co.uk