I have every sympathy for the school heads who are desperately trying to balance budgets with too little income. Sending letters to parents which pressure them into making "voluntary" payments is, however, not the way forward. Indeed it borders on illegality in that it flouts the intention of education law.
Parents should remember that state education in the UK is free. Any school that receives funding from the taxpayer signs a funding agreement in which they agree not to make any charges for education but are allowed to charge for voluntary trips.
Parents who agree to top up school incomes are not actually helping the long term future of education. If schools in affluent areas get plenty of top up income from parents then it leaves schools in poor areas starved of funds and providing a much worse service. This completely undermines the idea of decent education being provided for all our children.
We are facing a situation where the upper classes go to private school, the middle classes get reasonable education as a result of parental top up and the poor get dreadful sink schools trying to cope with completely inadequate budgets. As soon as middle class parents find that they are paying once through taxes and then again through a school levy it will not be long before they start agitating for their taxes to be cut and we move completely away from any idea of a universal free education service. Our towns and cities have already begun to be firmly divided by class because middle class families move to localities with good schools leaving inner city sink schools to flounder. Now this is to be further exaggerated.
Imagine the outrage if the NHS started to pressure patients to make top up payments. That is exactly what is now happening across the country in several schools. It has to be stopped before it becomes established practice.
I therefore suggest that parents should not pay any school that asks for top up income to cover its running costs and instead asks its elected representatives why it has been possible to pay for universal state education in this country since 1870 but the government refuses to do so now.