Trying to get long-overdue UK passport

Hi! I was born in the UK because my father was working on his dissertation there in British art history. For many years I figured it wasn't really worth the time and effort to pursue getting a UK passport, which I believe I can get due to being born in London. With the current state of the United States, I felt strongly compelled to pursue it now.

I’m pretty sure that being born in the UK before Jan 1, 1983 means that you are automatically a British Citizen. Getting a UK passport would be a nice bit of insurance in case you are ready to bale out of the USA for whatever reason.