The Universities and College Admission Service (UCAS) mediate all applications made to universities in the UK. You cannot apply directly to a UK university and therefore all applications must be made via UCAS using the dreaded UCAS form. This form requires you to enter your personal details, your course choices and most important of all your personal statement. Your UCAS personal statement is your opportunity to sell yourself to admissions tutors and convince them they should offer you a place at university over the 100’s of other applicants.
In conceptualizing a theme, you have to consider the main question, "What would you like to say with your essay?" For example, do you want the admissions committee to understand your choice of major and career in relation to your family background, or do you want to share your passion for your chosen field and your desire to achieve excellence in it? Whichever theme you come up with, this has to be unique to you as an applicant and should be related to your personal background, choice of major, and choice of career. The more unique a theme is, the more interesting the essay will be. In this sense, you can capitalize on personal facts you believe are noteworthy of exposition.