A Catholic school may be forced to change its admissions policy which favours children from families who are the most active in the church.

Saint Philomena’s High School for Girls, in Carshalton, is the sister school John Fisher School in Purley, which sees points awarded for parish activities such as having a child baptised in a Catholic church and attending Mass.

But a report by the Office of the Schools Adjudicator (OSA) has recommended John Fisher scrap the system after a parent had complained their points system was too complicated.

The school must inform the local diocese, Southwark, who could force St Philomena’s to follow suit if the policy is considered contrary to the Schools Admissions Code.

The system at both schools were introduced to deal with problems surrounding over-subscription.

Parents looking to send their child to John Fisher would need to reach the cut-off point of 65 points, but as the school does not restrict admission by geography, different parishes have different activities.

The objection to the OSA claimed this meant the governors could manipulate what was considered a bona fide parish activity to “exclude those they do not wish to admit from the school”.

The school adjudicator rejected this claim but agreed the current system was far too complicated and urged for it to be scrapped.

In the findings, Dr Ruth Eade said: “The issue of complexity needs to be as a matter of urgency.

“Accordingly, I suggest that the points system relating to involvement in parish activities should be replaced with another tie-breaker, e.g. distance from the school or a lottery.

“I make the strongest recommendation that the school and the archdiocese should collaborate during the autumn term in order to settle the matter in readiness for the 2010 intake.”

It is the second time the admissions policy has been investigated by the OSA after an initial complaint regarding its complexity was submitted in July last year.

On that occasion the objection was rejected but the adjudicator again advised the policy be urgently reviewed.

The latest ruling has been applied for only a year to ensure if the measures are not taken parents can resubmit their objections to the points system.

A second objection that governors were using parents surnames to reject single parents was also rejected by the adjudicator.