The Rev David Jennings, vicar of Burbage, Leicestershire: "This is the antithesis of what education is about - broadening young minds, not narrowing them."
Canon John Hall, the general secretary of the Church of England board of education: "There are conventions such as not proselytising to pupils which visiting groups should abide by. Any organisation which goes into a school can only do so with the authority of the head."
Allen Moxham, a spokesman for Youth for Christ, said: "If we were going in to hoodwink or brainwash people into joining us, it just would not be acceptable to schools. We would be kicked straight out of the door."
Lat Blaylock, executive officer for the Professional Council for Religious Education: "The language of 'discipling' is not appropriate in the context of religious education or a school assembly."
Sue Dempsey, head of special needs at Chiltern Trinity high school, Bridgwater, Somerset, which has had the Soundnation group in twice: "They are a fantastic group that the kids really listen to. Whether you are a Christian or not, you cannot help but enjoy seeing the interest that it sparks in the pupils."
The Rev Sior Coleman, chaplain and head of RE at Baverstock comprehensive, Birmingham, where Discovery, the youth wing of Agape, has worked for years:
"Discovery would admit its aims are ultimately to offer children a choice which involves the Christian faith. But it does so in conjunction with the school's wishes and with educational considerations very much to the fore."