I've decided to not join the Navy, how do I get out!?

The first step is admitting to your recruiter that your word is trash. That is all you have to do. Go see your recruiter and tell him you are a liar and your word means nothing. He will initiate the paperwork to confirm that you have no integrity and that will be the end of it. Thanks for wasting his valuable time and taking the time to come on here and trashing the country that has given you everything. Feel free to go see the Brits about work.