If you are over 18 and are of sound mind UK law enshrines the right for you to refuse and and all medical treatment up to and including that required to save your life.
You can refuse a swine flu jab in exactly the same way that you can tell a paramedic not to give you CPR (Presuming that you're awake at the time, that is).
Of course, as a nurse you may not be permitted to work with vulnerable people if you have not had the vaccine. You may have to do paperwork rather than ward rounds.