Baker Street is the London Underground station with the most platforms, having ten platforms serving multiple lines.
The station opened in 1863 as part of the Metropolitan Railway, the first underground railway. Its original Metropolitan line platforms are among the oldest surviving Underground platforms, while later construction added platforms for the Bakerloo, Circle, Hammersmith & City and Jubilee lines.
Baker Street's unusually large platform total reflects its importance as an interchange and the growth of London's railway network around the original Metropolitan route. The station is also closely associated with Sherlock Holmes, whose fictional address is 221B Baker Street.
A common mix-up is to assume that the busiest station must also have the most platforms. Passenger totals vary by year, but Baker Street's ten-platform layout is a separate, structural distinction.