15 Westferry Circus is a 16,250 m² (175,000 sq ft) building on Canary Wharf. Construction began in November 1998. Its finish marked the completion of the Westferry Complex, the westernmost point of Canary Wharf.
The building was designed to fully incorporate the requirements of the tenant, Morgan Stanley Dean Witter, who also occupied the adjoining building. Their lease began in March 2000, the same month Citigroup leased 25 Canada Square.
Morgan Stanley Dean Witter sublet the building to Tube Lines. They share the building leading to the video wall, built for use in stock trading but used as a Recovery Silver Control for the London Underground in the aftermath of the London Bombings. In 2013 Morgan Stanley vacated the building and it was taken over by London Underground Ltd, who had taken over Tube Lines.
15 Westferry Circus serves as the fifteen mile (24 km) marker in the London Marathon.
The ownership of this building was the subject of a protracted legal dispute in Ireland in 2012.