A school has been criticised for making pupils pay to study for a music GCSE.
Bingley Grammar School charges students £5 a week to take after school music theory classes.
The Incorporated Society of Musicians (ISM) has called the decision "shocking and deeply troubling".
Head teacher Luke Weston said it was not a result of funding issues and that the number of students studying music at the school had increased since the classes began.
Year 7 and 8 pupils at the school are still taught music during school time and the extra classes are only for those wishing to take the subject as a GCSE.
The charges were introduced in October.
Deborah Annetts, Chief Executive of the ISM, the professional body for musicians, said: "This new development is shocking and deeply troubling. Music is at risk of becoming the preserve of those who can afford it and the Government must act now to ensure it is available to all."
She said the ISM had written to the school "asking for them to reverse their policy".
Mr Weston said: "Last year we had two or three kids in class and now, having moved to our new system, we've got 25, which is more than we've had in the last five years.
"We've had no complaints from parents."
He said the introduction of the "nominal" charge was "nothing to do with funding, it's really allowing our kids to have an extra GCSE at a time that suits them".
Mr Weston rejected the suggestion that some children would be priced out of studying music saying support was available for those unable to pay.
He added: "We are paying 99.9% of the bill. The GCSE cost is not £5 a week, it's significantly more than that."