District of the City of Westminster.
Formerly a metropolitan borough, it was integrated with Westminster and Greater London in 1965. Three important landmarks of the district are Paddington station, designed by the celebrated engineer Isambard Kingdom Brunel and opened in 1847; St Mary's Hospital and Paddington Green Police Station (the most important high-security police station in the United Kingdom).
A major project called Paddington Waterside aims to regenerate former railway and canal land between 1998 and 2018, and the area is seeing many new developments.
More information on the Wikipedia page