How to learn the British accent? (From London)?

I'd love to learn the British accent, like, the one from London, England UK. 10 points to the best answer! Sites? Tips? Apps? (I have an iPhone.)

Listen carefully to how the Brits speak, then try to imitate them. It might take awhile for you to get it right, keep practicing and be patient

British accents are very sexy. ❤
Google how to master the British accent. Listen to many people speak and try to repeat how they say it. Listening and speaking and pronouncing are the best ways to master an accent, and even a language. The English babbel app may help if and only if it has the British accent. I'm not sure because I haven't used it, as I'm a native English speaker, but it does have the British flag on it. Try it out! Listen to the vocabulary pronunciation. Listening and repeating are the best ways. And patience, because it is a virtue in general.

At what social level?
For most of the younger generation, TH (except in the definitve article and the demonstarive adjectives and pronouns) is replaced by F or V (Bruv for brother, Fink for think, A fing of byoo'y is a joy frever).
Medial plosives tend to be replaced by the glottal stop (you aw'a for you ought to)
NG is replaced by N except in Finger: Huntin, shoo'in and fishin.
WH is always reduced to W, confusing which with witch, whales with Wales, whether with weather. And Hs are often dropped elsewhere, except in "herb".
The past subjunctive is never used: If i was 'er for If I were she.
The historic long U which now survives only in Scotland has passed well beyond its OW stage to become almost a long A: Ah nah brahn cah (How now, brown cow).
Colloquial Jamaican English has had a strong impact, expecially on the language of our feral youth: "The police is sussing everbody, innit?"
The practice of pronouncing R only before a following vowel leads to its incorrect insertion, hence "lore and ordugh" for "law and order".
Why on earth you should wish to acquire such an accent (usually known nowadays as Estuary English in reference to the lower Thames River) is beyond my comprehension.
v.