RP and estuary English

I have seen several references on this discussion forum to a certain type of accent referred to as "estuary English". I have surmised that it is something that is supposed to resemble RP. Can someone explain to me exactly what estuary English is? How does it differ from RP? Is it something like "near-RP"? My guess is that it is something close to RP which is used by young, urban, educated professionals who did not grow up in an RP-speaking background and who simply don't have the time, energy, or motivation to learn it.

However, my guess could very well be wrong. Even if my guess is correct, I would still like to know how estuary English differs phonologically from RP. I will settle for a brief, non-detailed explanation although long, detailed explanations are certainly welcome also. Thank you in advance for your responses.

Estuary English is a name given to the form of English widely spoken in South East England, especially along the river Thames and its estuary. It is a hybrid of Received Pronunciation (RP) and South Eastern accents, particularly from the London, Kent and Essex area. It first came to public prominence in an article by David Rosewarne in the Times Education Supplement in October 1984.[1] Rosewarne argued that it may eventually replace RP as the Standard English pronunciation.

Some people say (usually in jest) that it's called Estuary English because "It's as clear as mud and flows freely".

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Estuary English (http://en.wikipedia.org/wiki/Estuary_English)

Thank you kindly for your response.