Thinking about it, this could have a very negative impact on aircraft values, even grounding some as a result.
If things stand as they do, it's going to cost £ 3,500 for a mode S. Some aircraft, VP1, Fred are only just worth that alone.
This could really finish of the fun, low ish cost flying. The sooner we cast off europe and become the 53rd US state the better, well from an aviation point anyway.