What should I include in an introduction for a 25 mark question in a history a level paper?

Your first sentence should mirror the question - your examiner should be able to tell what the question is just by reading this sentence. Your introduction should outline the three main points/themes which you are planning to discuss in your answer without saying "In this essay i will discuss ...". It should be clear what you are going to discuss without saying it explicitly. An introduction should be finished by stating what your personal argument will be, however it is important not to use first person when doing this. This argument needs to be continued throughout the essay.
Your conclusion should replicate the introduction and solidify the argument which you stated in the introduction.