Hang the Bandit,
Don't give up hope!
Take your contract and go and see one of those soliciting folks (and not the type to be found outside a street corner on Frday nights).
If your employer is entitled to the three months notice, then they can try to get an order making you stay (probably not in their interest to keep a disgruntled employee) or they can try and claim cash from you for their "loss" (ie cost of replacing you) - which will probably not amount to too much.
If you did just leave, you have to bear in mind what everyone else has been saying, about how this will look to future employers.
Good luck
B