IIRC the current agreement not to build a second runway exists between BAA and West Sussex Council.
I think the actual point; is that if BAA sell Gatwick to a new owner then the previous agreement would be null and void!
The new owner not being the BAA, could then plan anything they wish; given consent by Government, and thus a new runway to the south as already planned for and who knows, a new terminal too could well be built before 2019.
About time too!
