[4][11] After plans to build the 92-storey Millennium Tower were dropped, 30 St Mary Axe was designed by Foster + Partners and the Arup Group.

[4][13] The Gherkin nickname was applied to the current building at least as early as 1999, referring to the plan's highly unorthodox layout and appearance.

[14] On 10 April 1992, the Provisional IRA detonated a bomb close to the Baltic Exchange, causing extensive damage to the historic building and neighbouring structures.

[15][16] English Heritage then discovered that the damage was far more severe than initially thought, and they stopped insisting on full restoration, albeit over the objections of architectural conservationists.

[18] The salvaged material was sold for £800,000 and moved to Tallinn, Estonia, where it awaits reconstruction as the centrepiece of the city's commercial sector.

John Prescott, the Deputy Prime Minister, granted planning permission on 23 August 2000 to construct a building on the site, which would be much larger than the old Exchange.

GMW Architects proposed a new rectangular building surrounding a restored exchange: it would have the type of large floor plan that banks liked.

The project was managed by RWG Associates, structural engineering was provided by Arup, and Skanska served as the main contractor.

[4] Architects promote double glazing in residential houses, which avoids the inefficient convection of heat across the relatively narrow gap between the panes, but the tower exploits this effect.

The building is visible over long distances: From the north, for instance, it can be seen from the M11 motorway, some 32 kilometres (20 mi) away,[25][26] while to the west it can be seen from the statue of George III in Windsor Great Park.

[27] The cost of repair was covered by main contractor Skanska and curtain-wall supplier Schmidlin (now called Schmidlin-TSK AG).

[25] The open-floor ventilation system did not operate as designed due to tenants adding glass partitions to increase security.

However, Ken Shuttleworth, who worked for Foster + Partners on the design of the building, said in 2011 that he believed the style was now out-moded: "I was looking at the glass all around and [thought], 'Why on earth did we do that?'

[38] Since February 2010,[39] Sky News has broadcast its flagship business programme, Jeff Randall Live, from a studio in the building.

[6] In the construction process of 30 St Mary Axe, a skeleton of a teenage girl was unearthed and dated as roughly 1600 years old.