About 18 months ago BA introduced a series of outrageous charges - £25 for picking up tickets at the airport, £25 for making a change at an airport ticket desk and £40 for refunding tickets. Legally they are correct to refuse to refund you the tax as the refund charge (this applies to full fare and refundable tickets as well) exceeds the refund due. This is another example of BA's shocking attitude to customer service.