What is estuary english

Estuary English is an English accent associated with the south east, especially the area along the Thames river and estuary.
What are the phonetic characteristics of Estuary English (EE)?

• l-vocalization, pronouncing the l-sound in certain positions almost like [w], so that milk bottle becomes [mɪok ˈbɒto] (almost like ‘miwk bottoo’), and football becomes [ˈfʊʔbɔo] (‘foo’baw’).
• glottalling, using a glottal stop [ʔ] (a catch in the throat) instead of a t-sound in certain positions, as in take it off [teɪk ɪʔ ɒf], quite nice [ˌkwaɪʔ ˈnaɪs]. This is not the same as omitting the t-sound altogether, since plate [pleɪʔ] still sounds different from play [pleɪ]. Nevertheless, authors who want to show a non-standard pronunciation by manipulating the spelling tend to write it with an apostrophe: take i’ off, qui’e nice. The positions in which this happens are most typically syllable-final — at the end of a word or before another consonant sound. London’s second airport, Gatwick, is very commonly called[ˈgæʔ wɪk] (“Ga’wick”).

• happY-tensing, using a sound more similar to the [ i:] of beat than to the [ɪ] of bit at the end of words like happy, coffee, valley. Many recent works on English phonetics transcribe this weak vowel as [i] which can then be interpreted in various ways according to the speaker's accent. In strong syllables (stressed, or potentially stressed) it is crucial to distinguish tense long [ i:] from lax short [ɪ], since green must be distinct from grin and sleep from slip. But in weak syllables this distinction does not apply — the precise quality of the final vowel in happy is not so important.
• yod coalescence, using [ t∫] (a ch-sound) rather than [tj] (a t-sound plus a y-sound) in words like Tuesday, tune, attitude. This makes the first part of Tuesday sound identical to choose, [ʧuːz].