London's Duplicate Image Problem: How the Capital Compares to New York, Tokyo and Amsterdam

London's planning and property system holds tens of thousands of duplicate images across its digital estate — outdated street-level photographs, recycled site renders, and mislabelled housing stock pictures stored across at least a dozen separate council and mayoral databases. The Greater London Authority acknowledged as far back as 2024 that data duplication across its digital infrastructure was a growing operational problem, and the issue has not gone away. If anything, it has compounded.

Why does this matter in July 2026? Because the Starmer government's planning reform agenda, anchored in the Planning and Infrastructure Bill currently before Parliament, depends heavily on digitised, accurate local data. Councils must publish standardised planning data by law under the Levelling-Up and Regeneration Act 2023. Duplicate and contradictory image records — showing demolished buildings, pre-development brownfield sites, or incorrect addresses — undermine the credibility of those submissions. In a city where more than 100,000 new homes are needed, bad visual data has planning consequences.

What London Is Actually Doing

The London Digital Twin project, managed through the GLA's City Intelligence unit, is the primary vehicle for cleaning and consolidating spatial data across the 32 boroughs. The programme uses automated deduplication tools to identify redundant records, including image files attached to planning applications on the Planning London Datahub, which went live in 2021 and covers submissions from all London boroughs. Southwark Council has been among the more active participants, integrating its local land and property gazetteer with the Datahub's image layers. Lambeth and Tower Hamlets are further behind, according to borough-level compliance data published by the Department for Levelling Up's successor body earlier this year.

The Museum of London's digital archive team, now based at their new Smithfield site, has separately worked with Historic England to purge duplicate heritage images from the National Heritage List for England — a problem that affects records for listed buildings throughout Bermondsey, Stepney Green, and Spitalfields. That work has been ongoing since late 2024, when an audit found roughly 18 percent of image entries for Grade II-listed structures in inner east London were either duplicates or misattributed to the wrong address.

How That Compares Globally

New York City offers a telling contrast. The NYC Department of City Planning migrated its ZOLA zoning and land-use database to a unified platform in 2023, incorporating image deduplication as a core feature. The city's open data team reported that the migration removed more than 340,000 redundant file attachments from public-facing records. London's equivalent consolidation effort is more fragmented, partly because planning authority in England remains split between borough level and the GLA, with no single system owner.

Tokyo's approach is arguably the most systematic. Japan's 3D city modelling initiative, Project PLATEAU, launched by the Ministry of Land, Infrastructure, Transport and Tourism, mandates standardised image metadata across all 56 participating cities. Duplicate image detection runs automatically before any new record enters the national urban model. Amsterdam's municipality went further in 2025, publishing a full audit of its Basisregistratie Grootschalige Topografie — the large-scale topographic base register — and found fewer than 2 percent duplication rates after a three-year clean-up programme that began in 2022.

London's rate is harder to pin down. The GLA has not published a standalone audit of image duplication across its platforms. Research published by the Open Data Institute in late 2025 estimated that duplication rates in UK local authority planning datasets ran between 12 and 22 percent depending on borough, with older and less-resourced councils performing worse. That range sits significantly above Amsterdam's figure and is difficult to reconcile with the government's stated ambition to make England's planning system fully digitised and interoperable by 2028.

Practically, Londoners dealing with planning applications — particularly homeowners on streets like Railton Road in Brixton or Caledonian Road in Islington where permitted development disputes are common — can check the Planning London Datahub directly at planningdatahub.london.gov.uk. If a property's associated images appear outdated or belong to a different address, borough planning departments accept correction requests under the Local Land Charges Act 1975. The GLA has confirmed the Digital Twin programme will publish updated deduplication metrics before the end of 2026, which will provide the clearest read yet on whether London is closing the gap on its European peers.