The Gherkin: How London’s Famous Tower Leveraged Risk and Became an Icon (Part 3)

The Gherkin: How London’s Famous Tower Leveraged Risk and Became an Icon (Part 3)

This four part series (originally published on Aggregate’s website) examines the Gherkin, the London office tower designed by Foster + Partners, showing how the urban icon engaged and leveraged perceptions of risk. In part one, author Jonathan Massey introduced the concept of "risk design” to describe how the Gherkin’s design managed the risks posed by climate change, terrorism, and globalization. In part two, Massey examined the building’s treatment of climate risk. In part three, below, he explains how the Gherkin redesigned the risk imaginary associated with terrorism.

Mornings the Zamboni scrubs the plaza. Moving across the pavement in parallel lines connected by tight turns, the sweeper cleans the stone of cigarette butts and spilled food and beer left the night before by the underwriters and bankers who patronize the bar and shops in the building’s perimeter arcade as well as the adjacent restaurant that in fair weather sets up outdoor tables and chairs.

By pulling away from its irregular property lines, the tower achieves almost perfect formal autonomy from its context. The gap between the circular tower base and trapezoidal site boundaries forms a privately owned public space, a civic and commercial amenity in this densely built part of the City. 

The portion of the plaza adjoining Bury Street provides seating for patrons of the restaurant in the six-story annex building. Photograph by author.

The plaza is much reduced in activity compared to what Foster + Partners envisioned during the schematic design and permitting phases of the project, but it is handsomely detailed with granite paving, including ramps and benches along the low walls that separate it from the adjacent streets.

This perspective sketch from fall 1998 shows how the base of the building might function as an airy retail zone extending below plaza level. Foster + Partners, Swiss Re House, Record Set of Presentation, 19th and 21st October 1998, 1998. Courtesy of Foster + Partners.

This residual urban space allows visitors and passersby to see the building’s curving sweep and to appreciate visually its formal coherence. The space also creates a security perimeter, a glacis or open zone permitting the 115 or so closed-circuit television cameras located on the premises to surveil all approaches. Within the building, access to the office floors is controlled by lobby turnstiles that admit staff by card swipe. Visitors must pass through airport-style security screening at an X-ray and metal-detector station to the right of the turnstiles behind the reception desk. Card swipes also control access from the elevator banks to the office floors above.

These techniques for monitoring and controlling access are standard for high-quality office space in the City. Financial services firms have constructed protected enclaves for their workers since the early 1990s, when the City responded to a series of Provisional Irish Republican Army (IRA) bombings by instituting new territorial strategies as a way to “design out terrorism.” [1] The Gherkin sits within the security perimeter known as the “Ring of Steel”: the array of access controls, barricades, automobile checkpoints, license-plate tracking, security cameras, traffic monitoring, parking restrictions, and stepped-up policing that encircles the financial services core of the City. By creating a nested series of security perimeters, the building reinscribes the Ring of Steel at multiple scales.

The plaza is one such device. Shielded by low walls and planters as well as by bollards capable of stopping a car or truck, the plaza provides “standoff,” the protective distance that mitigates the impact of a bomb blast. Another security perimeter is provided by the building’s structural system. The lateral stability of the perimeter diagrid provides superior blast resistance as well as structural redundancy in case part of the steel cage is knocked out by a bomb or vehicle. The curtain wall that clads the diagrid enhances the protection it affords: consultants who worked on the project noted that the building’s double-curving form—key to its deflection of wind—would significantly reduce the impact of blast forces in the event of another bombing adjacent to the site. Toughened and laminated glass sheets designed to flex and then break into harmless pebbles are set into deep, cushioned rabbets capable of absorbing additional blast energy. A decentralized and zoned heating, ventilation, and air-conditioning system, which draws air in through narrow vents between window courses at the edge of every floor and heats or cools it locally using circulating water pipes, eliminates the risk that a chemical or biological attack will travel through centralized air handling systems from a mailroom or main intake. [2]

By integrating an array of security measures into its design, 30 St. Mary Axe exemplifies the cultivation of resilience as a response to the threat of terrorism. (After the World Trade Center attack in September 2001—by which time the Gherkin’s pilings were already sunk, the steel purchased, and stairs and elevators locked into place—the architects, consultants, and developers performed a resilience check on the building. After concluding that the diagrid structure was likely to survive an airplane impact without collapsing, they strengthened bollards, added a guard station on the truck ramp, eliminated vendor carts from the plaza, and retrofitted what was to have been a property management office behind the lobby with airport-style X-ray and metal-detector screening for visitors.) [3] The building secures itself against anticipated forms of terrorist assault as well as can be imagined given its tight siting and provision for businesses and public uses in its base and plaza. In security jargon, its features provide target hardening designed to discourage attacks and direct them elsewhere through a carefully modulated combination of overt and implicit strategies. Bollards, visible cameras, and security checks encourage target substitution by generating security theater. But because many of the truck barriers are built into the landscaping, blast resistance is integrated into the overall building form, and air intakes are sublimated into curtain-wall joints, the building masks many more of its security measures from daily perception. [4]

The security provisions at 30 St. Mary Axe are not uncommon for new office buildings in the City, one of the world’s most heavily surveilled and secured open urban zones. But in this case, security features that the building shares with other prestige office buildings were not only determined by City conventions and policies; they were overdetermined by the profiles of the site and the client.

The property developer was able to purchase the St. Mary Axe property and secure planning permission for a tall new building in the midst of a tightly regulated historic preservation zone only because the site had been partially cleared in April 1992 when the Provisional IRA detonated a bomb consisting of one hundred pounds of Semtex and a ton of fertilizer inside a van parked at 28 St. Mary Axe. The blast severely damaged the listed neoclassical building housing the Baltic Exchange, the international shipping exchange that since the mid-eighteenth century has been part of the City’s financial sector and the global mercantile economy. The bomb also precipitated planning and policing studies that led to creation of the Ring of Steel following a second bombing one year later in Bishopsgate, just a block away from St. Mary Axe.

As it looked for a building in which to consolidate staff from offices at five London locations following its acquisition of Mercantile & General, Swiss Re considered thirty-three potential sites. Most were clustered in the City, but the range extended to the West End and the South Bank of the Thames as well as to the nearby Docklands. [5] When it agreed to purchase the St. Mary Axe site, the reinsurer negotiated a complex transaction that hinged on the seller securing planning permission for a new tower. Site options in the City were scarce, particularly in the area around the Lloyds insurance exchange and other industry firms. But the company had other options for consolidating, and it needed only about half the office space it intended to build, since much of the new building would be speculative rental space.

Increasing efficiency across Swiss Re’s London workforce and marking the presence of its expanded British operations were likely prominent motivators for company executives. But in choosing to consolidate its London workforce into a single tall building sited on the Baltic Exchange property, Swiss Re significantly increased its terrorism risk exposure. [6] Because the company’s business is reinsurance against risks, including those of terrorism, the exposure it purchased at 30 St. Mary Axe was not only a liability—it was also an asset. By highlighting the company’s commitment to managing terrorism risks through prudential planning, design, and policy, a distinctive new building on a symbolically charged site like this created value for the reinsurer as it expanded its activity in the UK market.

The more prominent the building, in fact, the greater the exposure—and the greater the potential branding value for a reinsurance company. The Foster design realized those benefits by capturing attention and branding the site with Swiss Re’s corporate identity. This dynamic made 30 St. Mary Axe an icon not only of climate change but also of terrorism risk management. The Gherkin was acclaimed in the insurance industry press by leading terrorism risk consultant Gordon Woo and selected to illustrate the cover of a book about blast effects on buildings. [7]

By soliciting risks and handling them ostentatiously yet seemingly effortlessly, 30 St. Mary Axe accrued capital for the clients and the City, for the architects and their consultants, and for design as a risk management practice. With each solicitation, gain, and management of risk, the design acquired agency by becoming a stronger branding instrument.

One dimension of the brand that this urban icon builds is an association with changes to British governance practices. Swiss Re’s selection of the St. Mary Axe site for its new building highlights the company’s participation in Pool Re (Pool Reinsurance Company Limited), the British mutual reinsurance system established in the wake of the Baltic Exchange bombing to keep premiums from becoming so high as to drive companies out of business—or out of the City and other terrorism target zones. Created in 1993, Pool Re spreads insurance liability for terrorist attacks and other catastrophes across all the insurers active in the UK market. Because extreme losses beyond predefined commitments made by private insurers are guaranteed by the British state, Pool Re spreads ultimate liability across the entire UK taxpayer base, socializing some of the most extreme risks borne by private insurers and reinsurers. [8] This collaboration between the state and a globalized insurance market in creating a new risk management regime is one of the neoliberal mechanisms for “governing at a distance” that have displaced the insular “club government” that prevailed in Britain, and particularly in the City, from the late nineteenth century to the late twentieth century: a tradition of self-regulation by private institutions and their socially vetted leaders operating viainformality, tacit knowledge, and autonomy from public scrutiny and accountability. [9] As both the UK headquarters of a major reinsurer and a valuable asset within the terrorism risk zone covered by Pool Re, 30 St. Mary Axe emblematizes the new arrangements whereby risk mediates British governance.

In the final installment, this article concludes by showing how the Gherkin engaged the risk imaginary associated with globalization to change the City of London’s economy, planning policy, and skyline.

Architect and historian Jonathan Massey is Laura J. and L. Douglas Meredith Professor for Teaching Excellence at Syracuse University, where he has chaired the Bachelor of Architecture program and the University Senate. A founder of the Aggregate Architectural History Collaborative and co-editor of its online journal, Massey is deeply engaged in shaping the ways we research architecture and its history. His book Crystal and Arabesque (University of Pittsburgh Press, 2009) showed how American modernist architects engaged new media, audiences and problems of mass society. His work on topics ranging from ornament and organicism to risk management and sustainable design has appeared in many journals and essay collections, including Governing by Design: Architecture, Economy, and Politics in the 20th Century (University of Pittsburgh Press, 2012).

Diagram by Andrew Weigand.

Andrew Weigand is a young New-York-based designer focused on how design affects the social and civil support systems underlying society. He operates at the intersection of public space with art, ecology, and infrastructure, working collaboratively across scales ranging from didactic graphics to architecture, urbanism, and landscape. Recent projects include a proposal for an infrastructural park in Queens, a habitat for meditation, furniture for an art education facility, a summer art pavilion, and a variety of illustrations.

Cite this piece as Jonathan Massey, “Risk Design,” The Aggregate website (Transparent Peer Reviewed),

[1] Jon Coaffee, Terrorism, Risk, and the City: The Making of a Contemporary Urban Landscape (Aldershot, UK: Ashgate, 2003), 28, 87.

[2] Schmidlin, “Swiss Re Tender Submission Volume II: Technical,” March 2000, in Foster + Partners Archives, F0000749245, Box: 8111/ID: 33834; and Sinisa Stankovic, interview, 27 September 2011. Regarding the building’s structural system, see Dominic Munro, “Swiss Re’s Building, London,” Nyheter om Stalbyggnad 3 (2004): 36–43.

[3] Robin Partington, interview, 3 October 2011.

[4] For an overview of the methods, logics, and history of the securitization of the City of London, see Coaffee. Exemplary of the rhetorics and analytical frameworks used by security consultants are Henry H. Willis et al., Estimating Terrorism Risk (Santa Monica, CA: RAND Corporation, 2005); and Henry H. Willis et al., Terrorism Risk Modeling for Intelligence Analysis and Infrastructure Protection (Santa Monica, CA: RAND Corporation, 2007).

[5] Foster + Partners, “Swiss Re House,” presentation, 19 October 1998; and “Swiss Re Environmental Statement,” May 2000. With planning consultancy Montagu Evans and real estate lawyers Linklaters and Paines, Foster + Partners provided the planning office with rationales for concluding that granting permission to the Gherkin would not obligate the office to grant similar permission to other developers. See Montagu Evans, Linklaters and Paines, and Foster + Partners, “Swiss Re House—Is It a Precedent?” planning report, August 1998, in Foster + Partners Archives, F0000746817.

[ 6] On gauging terrorism risk for buildings, see Willis et al., Estimating Terrorism Risk; Willis et al., Terrorism Risk Modeling; and E.S. Mills, “Terrorism and US Real Estate,” Journal of Urban Economics 51 (2002): 198–204.

[7] See “Critical Acclaim: Market Players’ Thoughts on the Gherkin,” Reactions, 1 June 2004; and David Cormie, Geoff Mays, and Peter Smith, eds., Blast Effects on Buildings, 2nd ed. (London: Thomas Telford, 2009).

[8] Lee Barnes, “A Closer Look at Britain’s Pool Re,” Risk Management 49, no. 5 (1 May 2002): 18; and Organisation for Economic Co-operation and Development, Terrorism Risk Insurance in OECD Countries (Paris: OECD Publishing, 2005), 255–260.

[9] Regarding “governing at a distance,” see Rose and Miller, 173–205. On the role of risk in such forms of governance, see Richard V. Ericson, Aaron Doyle, and Dean Barry, Insurance as Governance (Toronto: University of Toronto Press, 2003), 6. On “club government” and its demise, see David Marquand, The Unprincipled Society: New Demands and Old Politics (London: Fontana Press, 1988); Michael Moran, The British Regulatory State: High Modernism and Hyper-Innovation (Oxford, UK: Oxford University Press, 2003), esp. 1–11; and, more generally, David Kynaston, A Club No More: 1945–2000, vol. 4 of The City of London (London: Chatto and Windus, 2001). On the governmentality of Pool Re, see also Clive Walker and Martina McGuinness, “Commercial Risk, Political Violence and Policing the City of London,” in Crime and Insecurity: The Governance of Safety in Europe, ed. Adam Crawford (Cullumpton, UK: Willan Publishing, 2002), 234–259.

About this author
Cite: Jonathan Massey. "The Gherkin: How London’s Famous Tower Leveraged Risk and Became an Icon (Part 3)" 19 Nov 2013. ArchDaily. Accessed . <> ISSN 0719-8884

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