Is it possible to get into oxbridge postgrad with an unrelated undergrad?

I’m currently doing international business degree. I’m also planning on studying international relations or politics or history (I’m still weighing the options) for postgrad. I’m currently taking on multiple RA positions in politics. Is it possible for me to get into oxbridge for postgrad? Or should I apply for a second undergrad degree?

tl;dr yes, but I imagine you'll have to demonstrate academic ability and interest in your chosen area of politics, as well as why you didn't choose that for undergrad.

How was the original post too long for you to not read…

I admit this was a casual use of tl;dr, in which I used it as a shorthand for "summary of my thoughts", without actually writing the whole paragraph that normally precedes it. These things happen.

Alright. Thanks for the clarification. I was worried that human attention span had gone down the drain that one could not read 6 lines of text.