Smyrna (İzmir) has always been a busy and privileged trade node with its fertile Western Anatolian hinterland and naturally-protected harbour. During the 19th century, however, the city experienced an unprecedented trade boom and urban expansion mainly due to foreign industrial initiatives, modernisation projects, and its increasing importance in Mediterranean trade. Its port surpassed the size of Constantinople’s port, the Ottoman capital city, and Smyrna became an arena of commercial competition, especially attracting Britain and France. As the leading imperial power and world economic centre of the 19th century, Britain was the first to establish railways connecting Smyrna’s harbour to the hinterland as a modernisation project. British entrepreneurs bought 1/3 of Western Anatolian territory and ultimately controlled half of the port’s trade volume. Although the economic history of this shift towards semi-colonisation has interested many scholars, how its clandestine colonial makeup left traces on the city remains to be studied. Regarding post-industrial revolution port city development, Smyrna was an odd example since after the Tanzimat Reforms’, the modernisation strategies of different foreign investors, including the British, left a fragmented assemblage of urban spaces behind. The strange likeness of this assemblage to certain British colonial port cities rather than to port city models is worth exploring as new archival evidence shows that Smyrna was an incomplete imperial project formed in “British imagination”. This thesis aims to reveal how this informal empire embedded in modernisation acts was actualised, through morphological analysis combined with memoires, diaries and correspondances as the founding narratives of residual semi-colonial urban space.