The problem is most acute in inner-city areas, said Professor Gerald Grace, head of the Centre for Research and Development in Catholic Education at the Institute of Education in London. The temptation for heads in such areas is to recruit and concentrate on the brightest pupils to enhance the school’s measurable performance in the marketplace. “One of the many dilemmas facing Catholic headteachers,” he said, “is how to retain the integrity of their original mission, which was to serve the more deprived areas of the community, against the rising culture that every pupil must contribute to the success of the league tables.”

Professor Grace, who led a seminar on this topic at the institute this month, spent two years looking at 60 inner-city schools in London, Birmingham and Liverpool where “the dilemma was at its sharpest”. His study revealed that headteachers feel under pressure to recruit more able students, so sacrificing the wider mission of the school.

The drive to be more competitive has caused a conflict of interests. “The problem is that Catholic schools are tremendously successful with children from the more deprived areas,” he said, “but it is a success that is difficult to measure and is less visible than exam success.”

He suggested that one way to redress the problem would be to provide additional training. “The present NPQH qualification for headteachers is not enough. There needs to be a more sophisticated programme for all headteachers of faith-based schools so they can deal with the ethical and moral issues arising within their school.”

Profesor Grace also raised the question of the decline of what he described as “Catholicity” in schools. Falling attendance at churches has been cited as evidence that schools have failed to instil the Catholic faith in their pupils. But, he said, church attendance is a misleading measure of Catholicity. “The Catholic youth are critical of the standard form of the mass they experience in their church which is why attendance has fallen, but in schools, they are fully engaged in the liturgy because they find it lively and imaginative. What has happened is that schools have become the new living church for the young.”

He said this could lead to tension between the school and the church, but that it could be overcome if priests showed greater willingness to participate in schools. “While priests often have a high profile in primary schools, they seem ill at ease in secondary schools where the children can be more challenging. ”

One way to overcome this, he suggested, would be to provide better training, where young priests worked in schools.

The inner-city study and other findings are examined in Catholic schools: mission, markets and morality, to be published by Falmer Press next year.