The silhouette of the City of London has long served as a visual ledger of capital, its jagged peaks and glass facades charting the economic temperature of the United Kingdom. For decades, planning decisions within the Square Mile have acted as a precise barometer, measuring the capital’s confidence and its willingness to negotiate with its own profound heritage. In December 2024, the City of London Corporation’s Planning Applications Sub-Committee delivered a verdict that will physically and metaphorically redefine this skyline. They approved the revised plans for 1 Undershaft, a colossal 74-storey, 309.6-metre office tower that pushes against the very limits of what is permissible in the capital.
Designed by the acclaimed Eric Parry Architects, 1 Undershaft - often referred to during its protracted gestation as ‘One London’ - will definitively become the tallest building in the City of London. More significantly, it will exactly match the height of The Shard across the River Thames, making the two structures the joint-tallest buildings in the United Kingdom. Hitting the Civil Aviation Authority’s strict altitude ceiling, the tower represents the literal apex of the eastern cluster. However, the path to this historic approval was anything but straightforward, exposing deep-seated anxieties about the hyper-densification of the capital’s historic core. The fierce debate over 1 Undershaft was never merely about height; it was a fundamental argument about what, and who, the City is for in a rapidly shifting post-pandemic era.
A Protracted Architectural Evolution
The story of 1 Undershaft is one of persistent revision in the face of shifting civic, environmental, and commercial demands. The driving forces behind the project, Singapore-based developers Aroland Holdings and Perennial Holdings, working alongside prominent UK development manager Stanhope, first secured planning permission for a tower on this site back in 2016. However, that iteration remained unbuilt, a casualty of political uncertainty, Brexit negotiations, and subsequent global market shifts that fundamentally altered the financial landscape.
When the development team returned with an updated, slightly bulkier proposal intended to meet modern commercial and sustainability standards, they encountered a drastically altered planning environment. The Corporation was no longer simply waving through glass monoliths; they were scrutinising the street-level impact with unprecedented rigour. By mid-2024, the friction between the developers’ soaring ambitions and public realm preservation reached a crescendo. In July 2024, the City’s planning committee took the highly unusual step of deferring their decision. They mandated that Eric Parry Architects address severe concerns regarding the tower’s impact on the ground-level public space, specifically its dominant relationship with the adjacent St Helen’s Square.
The design team was forced into a rapid retreat to the drawing board. By October, amended plans were submitted, which involved pushing back the building line of the lower floors by ten metres. This crucial concession was designed to enlarge St Helen’s Square, introducing new public landscaping and mitigating the monolithic presence of the tower at street level. It was this calculated compromise that ultimately swayed the committee in December 2024, resulting in a decisive, albeit not unanimous, vote of 16 in favour to 7 against.
Engineering the Civic Skyscraper
To understand why the City Corporation ultimately approved such a massive addition to its eastern cluster, one must look to its ambitious ‘Destination City’ policy. Launched to counteract the severe hollowing out of the financial district during the pandemic, the initiative aims to transform the Square Mile from a monotonous Monday-to-Friday corporate enclave into a vibrant, seven-day-a-week cultural and leisure destination.
Eric Parry’s 1 Undershaft is the architectural manifestation of this policy. It attempts to actively hybridise the traditional corporate skyscraper with the civic institution. Moving away from the hermetically sealed aesthetic of previous generations, the approved design features a highly innovative, free-to-access elevated public garden on the 11th floor. This space is intended to provide the public with sweeping, mid-level views over the immediate historic surroundings, breaking up the sheer verticality of the structure.
More ambitious still is the crown of the building. The very top floors will house Europe’s highest publicly accessible viewing gallery, alongside a dedicated education centre. Crucially, these apex spaces will be curated and operated in partnership with the London Museum. These inclusions are not mere philanthropic gestures; they are strategic necessities. In the current planning climate, monolithic office blocks that turn a blind eye to the public realm are rarely viable. By integrating cultural spaces that draw the public 300 metres into the sky, the developers have effectively purchased their social licence to operate. The building aims to function as a vertical extension of the City’s public infrastructure, blurring the boundary between private enterprise and civic amenity. For further context on how these massive developments are reshaping the area, you can explore our detailed coverage of London City's amazing skyscrapers.
The Heritage Friction: St Paul’s and St Helen’s
Yet, not everyone is convinced by this utopian vision of a hybrid skyscraper. The approval of 1 Undershaft was fiercely contested by several prominent conservation bodies, most notably Historic England, acting as a statutory consultee. Their robust objections strike at the very heart of the ongoing, often painful debate concerning the City’s visual identity and historical legacy.
Historic England argued forcefully that the sheer scale and specific design elements of the tower - particularly a large, cantilevered podium structure - represented a “missed opportunity” that would “fundamentally compromise” the delicate character of St Helen’s Square. Furthermore, there was profound concern regarding the tower’s impact on the protected sightlines of St Paul’s Cathedral. The visual dominance of Christopher Wren’s 17th-century masterpiece has been systematically eroded over the last two decades by the relentless rise of the eastern cluster, a trend Historic England has consistently and vocally warned against.
Even after Eric Parry Architects revised the ground-floor footprint in October 2024 to yield more space to the public realm, Historic England maintained its rigorous objections. They specifically criticised the introduction of a large digital screen at the base of the building, arguing that such a modern intrusion could “arguably worsen” the impact on the historic public realm rather than improve it. The fact that the City Corporation approved the tower despite these formal, high-profile objections underscores a deliberate, calculated prioritisation of economic expansion and modernisation over strict conservationist principles. The tension between preserving the past and building the future remains the defining, often volatile narrative of contemporary architecture in the capital.
Commercial Viability and the Flight to Quality
The financial rationale behind constructing a 1.66-million-square-foot office tower at a time when hybrid working patterns remain deeply entrenched requires careful scrutiny. Why commit billions to such an immense scale when vacancy rates in older, secondary office buildings across London have steadily risen? The answer lies in the intense polarisation of the commercial real estate market, a phenomenon widely referred to by industry analysts as the ‘flight to quality’.
Major corporate tenants are increasingly abandoning secondary, outdated office spaces in favour of premium, highly sustainable, and amenity-rich environments. The logic is simple and ruthless: to mandate a return to the office, employers must provide physical spaces that significantly outperform the comforts of the home working environment.
1 Undershaft is designed precisely for this lucrative top tier of the market. The revised plans ensure the building meets stringent contemporary environmental standards, a non-negotiable requirement for blue-chip companies bound by strict ESG (Environmental, Social, and Governance) targets. While the overall volume of office construction in central London has experienced severe fluctuations over the past four years, data from analysts such as Deloitte consistently show resilient demand for Grade A, best-in-class space within the City core. Investors like Perennial Holdings and developers like Stanhope are betting heavily that the appetite for these superior corporate headquarters will only intensify over the next decade. They are building not for the market as it was in 2019, but for the highly selective market of the 2030s.
A Calculated Gamble on the Skyline
The approval of 1 Undershaft by the City of London in December 2024 is a watershed moment in British urban planning. It confirms, without ambiguity, that the City Corporation believes the path to economic resilience involves doubling down on extreme density, provided that such density incorporates tangible public benefits.
Eric Parry’s monumental design is a complex piece of urban problem-solving. It attempts to reconcile the immense commercial pressure to maximise rentable floor space with the civic necessity of an engaging ground level and a publicly accessible crown. Whether the 10-metre setback and the 11th-floor garden are sufficient to mitigate the sheer impact of a 309.6-metre wall of glass on the historic streetscape will not be fully known until the tower is built and occupied.
What is absolutely certain is that the London skyline is far from finished. The joint-tallest building in the UK will soon cast its immense shadow over the Square Mile. In approving 1 Undershaft, the City has made a clear, unyielding statement to its global competitors: it intends to remain a primary financial heavyweight, and it is entirely willing to aggressively reshape its historic skyline to prove it. The delicate balance of power between heritage preservation and vertical ambition has, for now, tipped decisively skyward.
