Complex sentence: Greater London continues to form the most closely associated parts of the Greater London Urban Area and their historic buffers so includes in five boroughs significant parts of the Metropolitan Green Belt which protects designated greenfield land in a similar way to the city's parks.
Split into simpler sentences: Greater London continues to include the most closely associated parts of the Greater London Urban Area and their historic buffers. Thus it includes, in five boroughs, significant parts of the Metropolitan Green Belt which protects designated greenfield land in a similar way to the city's parks.