City of London Since 1991 Canary Wharf, a few miles east of the City in Tower Hamlets, has become another centre for London's financial services industry which houses many banks and other institutions formerly located in the Square Mile. Although growth has continued in both locations, and there have been relocations in both directions, the Corporation has come to realise that its planning policies may have been causing financial firms to choose Canary Wharf as a location. Many major global companies have their headquarters in the City, including Aviva, BT Group, Lloyds Banking Group, Old Mutual, Prudential, Schroders, Standard Chartered, and Unilever. A
City of London Bridge, Tower Bridge and the Millennium Bridge. The City's flag flies over Tower Bridge, although neither footing is in the City. The size of the City was constrained by a defensive perimeter wall, known as London Wall, which was built by the Romans in the late 2nd century to protect their strategic port city. However the boundaries of the City of London no longer coincide with the old city wall, as the City expanded its jurisdiction slightly over time. During the medieval era, the City's jurisdiction expanded westwards, crossing the historic western border of the original settlement—the River Fleet—along Fleet