It will be a nasty step if you kick out your mother-in-law. Instead you should ignore her if she has done some mischief to you. For a while you should think about your spouse that how disgusting situtation will be for her. Act like a gentleman and try to win heart and let her realise her mistake and of course she will be repenting one day.
SteveoMc! I'm surprised at you! Don't you know mothers-in-laws are your best friends? They only want to help. Their only concern is your happiness and the smooth, harmonious functioning of the family -- no matter whose ass they gotta kick to make it harmonious and smooth.
Managing this is torture in the early years of marriage, from personal experience. And I am coming from the female POV. I have now been married 25 years and my mother in law and I have found a middle ground of respect and appreciation but it took a very very long time.
I believe you need to look at what is happening in your personal experience and be realistic about what you can and cannot handle. Is she living with you? What are the options? How can you help her find a good place either physically or emotionally? She must be very unhappy to make you respond in such a manner.
Unhappiness is contagious. If you care about yourself, you must not accept that this status quo is okay. You deserve a life without constant stress... can you accept that you are worthy?