radar707,
I remember when MAG were playing particularly hardball with NATS at the last contract negotiation. Some of us asked our managers why didn't NATS just call MAG's bluff and walk,knowing full well it would have left Manchester up a creek. Unfortunately (or fortunately, depends on your viewpoint I guess!) there are apparently clauses when these contracts are signed that in the event of a non renewal of a subsequent contract, there are mechanisms in place to prevent one side shafting the other. For example, the training of new controllers would potentially have to be provided by the outgoing ANSP so that when D-Day arrives, ATC provision doesn't come to a grinding halt for X months whilst the ANSP gets their staff trained up and validated.
Similarly, an agreement would be made regarding equipment and even things like MATS2 and other legal documents.
This is what we were told anyway....