London Councils Race to Fix Duplicate Image Problem Plaguing Planning Portal This Week

Planning departments across at least three London boroughs spent much of this week dealing with a duplicate image fault on the Greater London Authority's online planning portal, after applicants and objectors reported the same site photographs appearing attached to unrelated applications. The problem, which first surfaced on Monday 30 June, has since been flagged formally to the GLA's Digital and Technology team by officers in Southwark, Tower Hamlets and Hackney.

The timing could hardly be worse. The Starmer government's Planning and Infrastructure Bill is currently moving through Parliament, with ministers pitching digitised, transparent local planning systems as central to unlocking the 1.5 million homes target. A fault that muddies the evidentiary record on applications — even a temporary, technical one — hands critics a ready argument that the infrastructure behind the reform agenda is not fit for purpose.

What Actually Went Wrong

The issue centres on the document-management layer of the Planning London Datahub, the centralised repository that aggregates application materials submitted through the portal. According to a technical notice posted on the GLA website on 1 July, an update deployed the previous weekend introduced a metadata-tagging error that caused the system to associate image files from one application reference with neighbouring reference numbers in the database. Residents consulting the portal to review, say, a proposed development on Tooley Street in Bermondsey could find themselves looking at photographs of a site in Bethnal Green instead.

Hackney Council's planning department published a short advisory on its own website on Wednesday urging applicants and members of the public to cross-check physical address details before relying on portal images for comment submissions. Tower Hamlets sent a similar note to registered planning agents on Thursday. Neither borough confirmed how many live applications may have been affected, and the GLA had not issued a final remediation timeline as of Friday morning.

The Planning London Datahub went live in its current form in 2022 and now holds records for more than 80,000 planning decisions made across the 33 London boroughs. The platform is partly funded through the Mayor's London Plan Implementation Budget. Southwark's planning register alone handled more than 4,200 applications in the 2024–25 financial year, according to figures published by the borough.

Why Transparency Advocates Are Paying Attention

Groups that monitor development in the capital say the episode illustrates a structural risk in centralising planning evidence on a single platform without redundancy checks. The London Forum of Amenity and Civic Societies, which represents more than 100 neighbourhood and conservation groups from Hampstead to Greenwich, wrote to the GLA on Thursday asking for a full audit of applications decided between 28 June and 2 July — the window during which the fault was live and any public consultation responses submitted could have been based on wrong images.

There is a practical concern here that goes beyond inconvenience. Planning inspectors and local councillors are legally required to consider representations made during statutory consultation periods. If a resident submitted a comment on the wrong site photographs, it is unclear whether that comment would be treated as valid if a decision were subsequently challenged at appeal. The Planning Inspectorate, which handles appeals from England, confirmed in a brief statement that it was monitoring the situation but had not yet received any appeal referencing the fault.

The GLA said in its 1 July notice that a rollback of the problematic update had begun and that affected records would be individually reviewed by a technical team based at City Hall, near London Bridge. A corrected version of the update is expected to be redeployed before the end of July, the notice said.

For anyone who submitted a planning comment through the portal between 28 June and 2 July, the practical advice from borough officers is consistent: log back into the portal, verify that the images attached to the specific application reference match the address you intended to comment on, and resubmit if anything looks wrong. Objectors whose statutory comment window has since closed should contact their local borough planning department directly — Southwark's duty planning line is open weekdays at Tooley Street, Tower Hamlets' equivalent operates from Mulberry Place in Poplar. The GLA says it will consider extension requests where the fault can be shown to have affected a submission.