Duplicate Images in Council Planning Portals Are Delaying Decisions and Costing Londoners Time

Thousands of planning applications across London boroughs are being slowed by a technical problem that has largely gone unnoticed outside council IT departments: duplicate images uploaded to digital case management systems are clogging portals, creating processing backlogs, and in some cases forcing case officers to manually review the same document multiple times before a decision can be issued.

The problem matters now because London's planning system is under more pressure than at any point in recent memory. The Starmer government's push for accelerated housebuilding — backed by reforms to the National Planning Policy Framework introduced in late 2024 — means councils are expected to approve more applications faster. Sadiq Khan's London Plan targets well over 50,000 new homes per year. Any friction inside the system compounds delays that already run to months for major schemes.

Where the Bottleneck Bites

In Southwark, where the council's online planning portal handles hundreds of active applications at any given time, resident groups around the Old Kent Road regeneration corridor have flagged delays in receiving decisions on permitted development and householder applications. Officers dealing with duplicated file uploads — where an applicant or agent submits the same site photograph, elevation drawing, or heritage document twice under different file names — must reconcile the discrepancy before the case can progress. The council's planning department did not respond to a request for comment by publication time.

In Hackney, the situation is compounded by the volume of applications near the Dalston and Stoke Newington conservation areas, where heritage documentation requirements mean applicants frequently submit large batches of image files. When those files are duplicated — either through agent error or system glitches in the upload interface — officers can spend significant additional time on case administration rather than substantive assessment.

The Greater London Authority's Planning London Datahub, which aggregates case data from all 33 London boroughs, has been working since 2023 to standardise how application documents are submitted and stored. Deduplication of digital assets is one of several data quality improvements the Datahub programme has identified as a priority, though the timeline for borough-level implementation varies considerably.

What It Costs Communities

The practical impact on residents is concrete. A householder applying for a rear extension in Lewisham pays the standard planning fee — currently £258 for a householder application as of the April 2025 fee revision — and then waits. The statutory target for a decision is eight weeks. When officer time is absorbed by administrative errors like duplicate images, that window stretches. Applicants who miss the eight-week threshold can appeal to the Planning Inspectorate on grounds of non-determination, but that process adds months and cost that most homeowners cannot absorb.

For community infrastructure projects, the stakes are higher. Organisations applying for change-of-use consent for a community hall, a health clinic, or a neighbourhood food hub face the same portal problems with larger consequences. Voluntary groups running small capital projects on tight grant timelines — particularly those funded through the Mayor of London's Good Growth Fund, which has supported projects across Waltham Forest, Croydon, and Greenwich — cannot easily absorb a six-week administrative delay caused by something as mundane as a duplicated JPEG.

Planning technology firms operating in the UK market, including those already contracted to boroughs such as Ealing and Tower Hamlets, offer automated deduplication tools as part of modern document management suites. Several boroughs have not yet upgraded from legacy systems that pre-date the post-pandemic shift to largely digital submissions.

Residents dealing with pending applications should check their borough portal regularly and consider contacting their case officer directly by email to confirm all submitted documents have been recorded as distinct files. Applicants using agents should request explicit confirmation that the document pack submitted contains no duplicate file names before the application is validated. Those in areas covered by active regeneration frameworks — including the Old Kent Road Opportunity Area or the Meridian Water development zone in Enfield — face more complex multi-document applications where the risk of duplication is correspondingly higher. Raising the issue with borough ward councillors is also an option, given that planning committee oversight can prompt procedural improvements at departmental level.