Parents at St Anthony's RC school were furious at being told they were insufficiently devout for their children to take the weekly after-school preparation classes which will lead to taking the sacrament of Holy Communion next June. This major rite of passage is, along with baptism and confirmation, essential for full participation in the Catholic Church's rituals.
The Rev Richard Moroney, of St Anthony's church, says teaching children who have no religious home life "is like trying to teach arithmetic to children with no knowledge of numbers". But many parents say they are just unable to attend mass regularly.
The row cuts to the heart of the nature of church schools. Parents most aggrieved by the new rules believe they have already demonstrated their commitment to the church by attending an interview with the head and Father Moroney's predecessor when they enrolled their children at the school.
But church schools have long proved popular with non-religious parents because they often score better results than neighbouring, non-denominational schools.
Around 15 children from this year's Year 3 classes have been accepted onto the course, compared with more than 50 who took part last year.
Father Moroney, who doubts the religious convictions of some parents, said:
"Children are eligible if their parents have brought them up in the practice of the faith, which would include teaching them to pray, some knowledge of Jesus and some introduction to the liturgical life of the church by attending mass more or less regularly.
"When I did the course last year, I found very few of the children had been brought to mass since baptism and I found it very difficult to teach them." The Bishop's office in Northampton talks of poor behaviour at last year's ceremony.
The Bishop's office is not getting involved. It says arrangements are up to the local priest, but they should be "flexible in view of the situation of each child and family".
Catherine Flanders, whose seven-year-old daughter Laura was rejected, said she took her children to mass roughly every two months and was married by Father Moroney.
"Laura is quite upset. Father Richard has stopped children getting one step closer to God. I was brought up to believe you don't turn people away. To me, being a Catholic was about understanding, tolerance, patience and love."