Estuary English 
noun [mass noun]
(In the UK) a type of accent identified as spreading outwards from London and containing features of both received pronunciation and London speech: the upper-class young already talk Estuary English...
- It's just that when I call my electricity provider I rather hope to hear a London accent, or perhaps even a grating example of Estuary English.
- I mean, I know she's been living in Walford for a bit now, but even so… do accents just go like that, to be replaced with something that veers between Estuary English and slightly posh?
- I migrated to Australia in 1960, and so have missed the rise of Estuary English and the ascendancy of the glottal stop in the UK, which John Sturrock discusses.