It was built by Taylor Woodrow Construction as one of only four high-rise buildings in London using a top-down engineering design where the lower office floors are suspended from above rather than supported from below.

[2] In 1992, the building was heavily damaged in the Baltic Exchange bombing carried out by the Provisional IRA, as a result of which it was substantially renovated.

[7] In 1961, the Commercial Union Assurance Company had acquired a site in St Mary Axe, in the City of London, which it desired to develop as its new headquarters.

At the same time, the Peninsular and Oriental Steam Navigation Company was planning to redevelop its city offices in Leadenhall Street.

As a result, the two companies decided to participate in a joint development that would involve the reallocation of site boundaries and the creation of an open concourse area at the junction of Leadenhall Street and St Mary Axe.

Pedway was an ambitious but ultimately unfulfilled scheme to improve traffic flow in the City of London by means of the construction of a network of elevated pedestrian walkways.

The requirement was unpopular with designers, who regarded the results as visually unappealing unused space that often provided pedestrians with dead ends.

In 1970, the Commercial Union and Peninsular & Oriental buildings won the Civic Trust Award for townscape and design co-ordination.