Leeds Takes Methodical Approach to Duplicate Image Problem Reshaping City Archives Globally

Leeds City Council's digital records team has been working since early 2025 to address a problem that has quietly accumulated across decades of planning applications, regeneration project files and community archive submissions: thousands of duplicate images clogging the city's digital infrastructure and slowing down access to public records. The scale of the backlog, first flagged internally during an audit of the West Yorkshire Combined Authority's joint asset management platform, prompted the council to begin a phased deduplication programme that is now approaching its second year.

The timing matters. Across the world, cities are digitising vast volumes of historical and bureaucratic material at pace, and the duplicate image problem is emerging as one of the more stubborn practical consequences. In Amsterdam, the city's Stadsarchief launched a machine-learning-assisted review of its photographic collections in 2024. In Toronto, the municipal government acknowledged in its 2025 open data strategy that redundant image files were inflating storage costs and undermining search accuracy in public-facing planning portals. Leeds is not alone in grappling with this, but how it responds will shape how the city's digital infrastructure holds up over the next decade.

What Leeds Is Actually Doing

The council's Digital Services directorate has been running the deduplication work primarily through its Enterprise Content Management system, which handles files submitted to planning, highways and housing teams. According to the council's own published digital transformation roadmap — updated in March 2026 — the programme targets records held across Merrion House on Merrion Way, the civic hub that consolidated several council departments following office rationalisation in 2023. A secondary tranche of files originates from the Thoresby Place archive unit, which holds decades of urban development photography from inner-city neighbourhoods including Holbeck, Burmantofts and Harehills.

Leeds City Council has partnered with Jadu, a UK-based digital platform provider that has also worked with Sheffield and Bristol city councils, to assist with automated flagging of near-duplicate image files. The approach differs from Amsterdam's, where the Stadsarchief used bespoke machine learning models trained specifically on heritage photography. Leeds is relying more heavily on hash-matching and perceptual similarity algorithms applied across standard document management workflows — a pragmatic choice, but one that critics of such programmes argue misses contextually significant variants that might look identical to software but carry different evidential value in planning disputes.

Bristol, often cited as a peer city by Leeds officials in benchmarking documents, began a similar exercise in 2023 through its OneCity digital programme and reported removing roughly 340,000 redundant files from its planning portal within eighteen months. No equivalent figure has been published by Leeds Council to date, though the March 2026 roadmap references a target of processing at least 60 percent of pre-2015 image records by the end of the 2026-27 financial year.

The Risk of Moving Too Fast — or Too Slow

The global experience suggests two distinct failure modes. Cities that rush deduplication without robust human review risk permanently deleting files that carry legal or historical significance. Cities that move too slowly — as some observers argued Toronto did between 2022 and 2024 — find the backlog compounds faster than it can be cleared, particularly when live planning applications continue adding new images daily.

Leeds submitted more than 4,200 planning applications in the twelve months to April 2026, each typically accompanied by multiple photographic site assessments. That volume means the deduplication programme is running against a live, growing dataset, not a static one. The Kirkgate Market area regeneration files alone, active since 2021, are understood to contain several overlapping photographic surveys commissioned by different contractors at different stages.

Residents or community groups who have submitted photographs as part of planning objections — particularly in areas like Chapel Allerton or the South Bank regeneration zone — are advised by the council's digital team to retain their own copies of submitted images and to request confirmation of receipt when lodging files through the Leeds Planning Portal at leedsplanning.co.uk. The deduplication process does not affect publicly submitted objection documents, the council has stated, but given the scale of the exercise, independent retention remains prudent for anyone involved in active or pending applications.