Accents originally from the upper-class speech of the London–Oxford–Cambridge triangle are particularly notable as the basis for Received Pronunciation.
Southern English accents have three main historical influences:
The London accent, in particular, Cockney. [However, London has continuously absorbed migrants throughout its history, and its accent has always been prone to change quickly]
Received Pronunciation ('R.P.').
Southern rural accents, of which the West Country, Kent and East Anglian accents are examples.Relatively recently, the first two have increasingly influenced southern accents outside London via social class mobility and the expansion of London. From some time during the 19th century, middle and upper-middle classes began to adopt affectations, including the RP accent, associated with the upper class. In the late 20th and 21st century other social changes, such as middle-class RP-speakers forming an increasing component of rural communities, have accentuated the spread of RP. The south-east coast accents traditionally have several features in common with the West country; for example, rhoticity and the a: sound in words such as bath, cast, etc. However, the younger generation in the area is more likely to be non-rhotic and use the London/East Anglian A: sound in bath.After the Second World War, about one million Londoners were relocated to new and expanded towns throughout the south east, bringing with them their distinctive London accent (and possibly sowing the seed of Estuary English).