Church leaders have accused a Yorkshire council of putting a "tax" on Catholic families, by planning to end free travel grants for faith school pupils.
Under new plans for the Bradford district, children going to faith schools would only get a free travel subsidy if they also qualified for free school meals.
Campaigners against the plans are furious, and St Mary's Catholic School, a secondary school in Menston, has circulated a petition of protest.
The petition points out that "Catholic schools are an intrinsic part of state school provision and it is for this reason free transport has always been provided, as it would be to any other state school, to Catholic children living more than three miles (two miles if under eight) from their nearest Catholic school.
"All local state schools are oversubscribed, therefore if Catholic families chose not to attend our schools this would deny places to other local children.
"The right of Catholic parents to send their children to a Catholic school is enshrined in the 1944 Education Act and the most recent guidance from the Secretary of State asks Local Authorities not to disturb well-established arrangements."
The chairwoman of The Bishop Wheeler Catholic Academy Trust, Caroline Hyde, has written to Bradford Council, claiming that families will suffer "financial difficulties". The Trust runs six schools in the county.
She points out that parents with three children may have to spend an extra £1,000 a year to cover travel costs if free transport is withdrawn.
According to the Yorkshire Post, she wrote: "This policy appears to be based on the assumption that Catholic families will be willing and able to cover these additional costs and in essence this becomes a 'tax' on Catholic families.
"This will again be a disproportionate burden placed on Catholic families and one which will be a real challenge to all but those on the highest incomes."
Thomas Rothwell, acting co-headteacher of St Mary's in Menston, said in the same paper: "We are concerned that this new proposal will discriminate against Catholic families who cannot afford to pay the additional transport costs.
"Should Catholic children not come to St Mary's, Menston, they may exercise their right to attend Ilkley Grammar School. This may mean there are no longer enough places available there for local children.
"The authority would then have to pay to transport them to the nearest available school, thus negating any cost saving."
John Grady, a spokesperson for the Diocese of Leeds, said the diocese wanted the Council to retain the current free transport provision.
Councillor Ralph Berry, Bradford Council's portfolio holder for Children and Young People's Services, told the Yorkshire Post: "We do not want to have to do this but we are having to live within the very restricted means we have been given by Government."
Leeds Council has also recently revised its policy on this issue, planning a gradual removal of free transport for faith school pupils.
Leeds Council spends £4.76 million on free school travel that is not legally required every year. They are attempting to find £54.9 million in savings over the year 2013-2014.
The National Secular Society has praised Bradford Council's decision. It claims that the council "should be applauded for proposing the removal of this religious privilege and looking to create a more equitable school transport policy that's fairer for all families and at the same time removes an unnecessary burden on the taxpayer".
The Society's campaigns manager, Stephen Evans, added: "If parents wish to send their children to a school with a particular religious ethos, the associated transport costs should be their responsibility, not the responsibility of the state."
A spokesperson for the Catholic Education Service opposed the move: "We'd urge local councils not to take the soft option of cutting transport to faith schools.
"These schools have larger catchment areas and the cuts have a disproportionate effect upon families' ability to send children to the school of their choice."