The station was opened by the
Central London Railway (CLR) on 30 July 1900 with the name
Post Office, after
the headquarters of the
General Post Office on nearby
St. Martin's Le Grand. The name Post Office was possibly chosen instead of the more obvious St. Paul's to differentiate it from a
South Eastern Railway (SER) station which already held that name (but which today is called
Blackfriars). , on the blue
Central London Railway line. The station entrance was originally located on the north side of Newgate Street, on the west side of the junction with King Edward Street, but was moved to the east when the station was modernised in the 1930s with an underground ticket hall and
escalators. A modern ventilation shaft in the centre of the traffic island at the junction indicates the location of the original lift shafts. When the SER station called St. Paul's was renamed as Blackfriars in 1937, the Underground station called Post Office took the name '''St. Paul's''', which it has kept ever since. At the end of the 19th century, Newgate Street was a narrow road with some of its
medieval character remaining. To reduce land purchase and compensation payments, the CLR routed its tunnels directly under public roads. At St. Paul's the narrowness of the road required the tunnels to be placed one above the other with the westbound tunnel uppermost. The
lifts originally operated to a level between the two platforms, with stairs up or down to the platforms as necessary. A high-level access passageway is visible at the lowest level leading to the disused lift lobby. During the
Second World War the electricity grid control room for London and Southeast England was housed below ground in the lift shaft. ==The station today==