Mmmm.. No plans to make Mode S compulsory?
The present proposals would allow you to use uncontrolled airspace in the UK without one and the French will allow you to use much of their airspace without one. However, the CAA proposals would not allow you to cross the FIR boundary without one!
I also heard it said that at the moment there is no such thing as a Mode S transponder, only composite mode A,C and S ones. If that is the case, I wonder how much cheaper a mode S only one would be.