London Councils and Developers Rush to Fix Duplicate Image Problem Plaguing New Planning Applications This Week

Planning departments across at least three London boroughs spent much of this week returning incomplete applications to developers after discovering that digital portals had accepted duplicate images — sometimes the same photograph filed dozens of times — as separate supporting documents. The problem, which emerged publicly on Monday when the Greater London Authority's development portal flagged a batch of submissions for the Stratford Waterfront Phase 3 scheme, has created a backlog that officers are now working to clear before the August recess freezes most committee decisions.

The timing is awkward. Keir Starmer's government has made planning reform a centrepiece of its housing agenda, leaning heavily on local authorities to speed up decision-making and reduce the number of applications that drag past their statutory eight-week target. Any technical failure that adds delay runs directly against that political pressure — and against the targets set out in the National Planning Policy Framework revision published earlier this year.

What Went Wrong, and Where

The issue appears to centre on a file-upload function within the Planning Portal's 1APP system, the standardised application form used by councils across England. When applicants upload a folder of images rather than individual files, the system has, under certain browser conditions, registered the first image in the folder as every subsequent entry. Tower Hamlets Council confirmed it had identified affected applications on its caseload this week, as did Southwark Council, which administers a particularly heavy volume of major applications given ongoing regeneration around Old Kent Road and Bermondsey. Lambeth officers flagged the same pattern in submissions linked to sites near Brixton and Clapham Junction.

For developers, the practical consequence is a formal notice of invalidity — meaning the application's statutory clock stops and the eight-week countdown does not restart until a corrected set of images is resubmitted and validated. On larger schemes where pre-application fees already run to tens of thousands of pounds, even a two-week interruption carries real cost.

Planning Portal's operator, TerraQuest Solutions, acknowledged the fault in a technical notice circulated to local planning authorities on Wednesday, 1 July. The company said a patch would be deployed by the end of this week. Applicants who submitted between approximately 16 June and 30 June are being asked to check their submission receipts and resubmit corrected image files if they see any discrepancies in the document list.

Practical Steps for Applicants and Their Agents

Chartered surveyors and planning consultants operating in London have been advising clients since Wednesday to log back into the Planning Portal, download their submitted document packs, and compare the image file names line by line. The Chartered Institute of Building's London branch sent a short guidance note to members on Thursday morning flagging the issue, and the Royal Town Planning Institute's regional network circulated similar advice through its mailing list.

For homeowners managing smaller applications — permitted development notifications or householder applications for extensions — the risk is lower but not zero. A single duplicated site photograph does not automatically invalidate a submission, but it can trigger a request for further information that adds three to four weeks to a decision. In boroughs such as Hackney and Islington, where householder application queues were already running at 11 to 12 weeks as of the most recent published figures from April 2026, that kind of delay compounds quickly.

The GLA has asked all major applicants with live applications submitted in the affected fortnight to contact their case officer directly rather than waiting for an automatic invalidity notice. For schemes on the Mayor's call-in list — broadly, applications over 150 residential units or more than 30 metres in height — the authority has said it will not start its own consultation clock until a clean image set is confirmed.

TerraQuest has committed to posting a full incident report by 11 July. In the meantime, planning agents say the safest approach is to upload images one at a time rather than in batches, name each file with a unique alphanumeric prefix, and retain a local copy of every document in the order it was submitted. For schemes with committee hearings scheduled in September — the first full cycle after the summer recess — this week's correction window is the one that matters.