The exact northern extent is hard to define. In the west it could include Gloucestershire and Oxfordshire, but then these are sometimes considered part of the Midlands.
South East England is one of the nine official regions of England.
In unofficial usage the South East can refer to a varying area - sometimes only to Kent, East Sussex, West Sussex, and Surrey or very approximately to the London commuter belt or the "Home Counties".
Traditionally the middle class inhabitants of the South East have spoken received pronunciation (also known as "RP", BBC English and Queen's English).