Speaking with a native accent (of any country) is considered really difficult! There are people living in britain/america/australia for years and still sound foreign. With that said, I like to think it's possible! And I've heard people from other countries speak English without a foreign accent. How difficult it will be depends on a lot of factors: how close your accent is to a British accent, how good you are at picking up different accents, and how much exposure you have to the British accent. If traveling to the UK isn't an option for you just now, watch as much British tv shows and movies as you can, speak to British people, etc. Really try to emulate how they speak as closely as you can, you'll feel silly at first but to us you probably sound just fine! Remember, there really is no such thing as a "British accent". There are four countries in Britain and each have their own distinctive accents. Scotland has two main accents, I've no idea how many accents Northern Ireland and Wales have (since I've never been to either) and England has A LOT of accents! Three main northern English accents, Two main 'midlands' accents, three or four London accents, an Essex accent, an East Anglian accent (technically two, but one is only very subtly different from London that you'd only be able to tell the difference if you lived there), a West country accent (probably more than one!), and very likely even more! Luckily for you, most British movies have quite a generic southern English accent. Don't worry too much about mismatching things, if you try to mimic how British people talk, and do it well, we'll probably be able to place you somewhere (even if you've never been there).