2005 MG ZR steering

You know you're going to have to elaborate on that or add some observations or clues. Does this happen in a parking lot? On the highway? What exactly is happening?

You've provided way too much information to make any kind of diagnosis. I don't know if the back end is sliding out because you're running from the cops, the front end is sliding because you have the brakes locked up, if a part is loose and this only happens when turning in one direction and not the other, the body is leaning excessively due to a broken anti-sway bar link, etc. You're going to have to visit a tire and alignment shop and let the mechanic drive the vehicle to see what is happening, and then inspect the steering and suspension components. I don't have a clue.