London's Planning Portals Hit by Duplicate Image Crisis — Here's What Changed This Week

A software fault that caused duplicate images to overwrite or obscure original planning documents on borough portals came to a head this week, prompting emergency reviews at the Greater London Authority and at least four local councils. The problem, which affects how uploaded site photographs and architectural drawings are indexed, has been quietly disrupting planning applications since late May but escalated sharply in the final week of June when a backlog of summer applications flooded the system.

The timing matters. The Starmer government's Planning and Infrastructure Bill, currently before Parliament, is pushing local authorities to process housing applications faster and shift more of the paper trail online. Any weaknesses in digital document management now carry real political weight — councils that can't demonstrate reliable online systems risk losing permitted development powers under reforms the government wants in place by spring 2027.

Which Boroughs Are Affected and What's Being Done

Southwark Council confirmed this week that its Uniform-based planning portal had flagged duplicate image tags on at least 34 live applications filed between 1 June and 28 June. Neighbouring Lambeth reported a smaller batch of around a dozen affected submissions, primarily householder extension applications in the Streatham and Tulse Hill areas. Both councils said they were working with their shared software provider to manually audit the affected files before any decisions are issued.

The Bartlett School of Planning at University College London on Gower Street has been tracking the rollout of digital planning tools across English councils since 2023. Academics there have noted in published research that image duplication errors — where a file upload system assigns the same metadata tag to two different photographs — are among the most common failure points when older Uniform or Idox platforms are integrated with newer cloud storage layers. The GLA's own digital planning team, based at City Hall on the South Bank, is understood to have contacted affected boroughs this week to offer technical support, though no formal advisory has yet been published on the planning.london.gov.uk portal.

For individual applicants, the practical consequences range from minor delays to outright confusion. An architect submitting drawings for a rear extension in Peckham, for example, might find that the planning officer reviewing the case is looking at a photograph from a completely different property — an error that could trigger a request for resubmission and add weeks to a decision timeline. The standard eight-week determination window for householder applications is already under strain: according to the Department for Levelling Up, Housing and Communities' most recent planning statistics release covering the year to March 2025, London boroughs determined only 76 per cent of major applications within the statutory 13-week period.

What Applicants Should Do Right Now

The immediate advice from planning consultancies operating in the capital — including firms based in Gray's Inn Road and around Victoria Street — is to log in and manually verify every uploaded document on any live application. Specifically, applicants should cross-check the thumbnail images shown on the public-facing portal against the original files they submitted. If any image appears to be mismatched or duplicated from another file, the case officer should be contacted directly by email with a corrected file attached, rather than waiting for the council to flag it.

Camden Council, which uses a separate Idox platform rather than Uniform, said this week it had not identified the same fault on its system. Hackney, Tower Hamlets and Islington are each conducting precautionary checks on submissions filed in June.

The GLA has not yet set a public deadline for a full resolution, but sources familiar with the City Hall digital planning team suggest a patch or updated guidance document could be circulated to boroughs before the end of July. Anyone with a planning application currently pending in Southwark or Lambeth should check their portal account before 11 July — the date by which both councils have said they aim to complete their manual audits — to avoid unexpected resubmission requests that could push decisions past the August bank holiday recess.