Here's a list of top British movies that I would largely agree with: http://www.bbc.com/culture/story/20150908-your-11-favourite-british-films But it may mean what you mean by "British English". If you mean Received Pronunciation, you'll find that especially in some of the older movies, where the actors have almost painfully clear and clipped elocution (probably a result of the classical stage training they generally had in those days). There are also some older American films that have actors with glass-cutting RP accents, such as Julie Andrews in The Sound of Music. At the other end of the spectrum, that list has Trainspotting, which may be a bit of a challenge for you. Good movie, though.

If you want an idea of regional accents and supposed every day life, with far more drama, than most people have then try the "soaps" - EastEnders (based in London) and Coronation Street (Manchester) are very famous ones. I hope Sherlock Holmes and Dr Who are not the rest of the worlds impression of Britain. Although I hope the soaps aren't either!! If you like dramas from history try "Downton Abbey" or "Call the Midwife".

There are lots of films with British accents. There are two hundred-eleven Sherlock Holmes movies, two dozen James Bond movies (although these are set around the world, so you might hear other accents as well, depending on where the film is set), eight Harry Potter movies, seven Lord of the Rings/The Hobbit films and four Monty Python movies. Here's a list of movies you can watch if you want to hear a particular accent: http://www.englishlessonsbrighton.co.uk/11-great-films-listening-british-accents/ There are also a lot TV shows you can choose from. I've already mentioned that there are two hundred and eleven Sherlock Holmes movies... there are also at least twenty-nine serial Sherlock Holmes TV series based on the list provided by Wikipedia. I suspect across all the Sherlock Holmes books, shows and movies, there's enough material to give a learner enough practice to increase their English from an A1 to at least a B2 level :-D One of the most well-known British TV series is Doctor Who. I've never watched it, so I have no idea what it's like; but according to Google there are 813 episodes for you to choose from! Game of Thrones is an American series, but just about every actor has a British or Irish accent of some kind. It's the most popular TV show in history (and the most pirated too), and season six is coming out in April. It's not nearly as good as the books it's based on (the show has replaced a lot of plot scenes with sex and fighting scenes, especially in seasons 4 and 5). Still, the show's good, and the first three seasons are phenomenal. Here's a list of British TV shows: http://www.complex.com/pop-culture/british-tv-shows-you-should-be-watching/

Find some British youtubers, generally, youtubers share videos on a daily basis and their videos are so spontaneous and they show their language. wau of thinking, daily activities, places, culture and much more... good luck