London's Planning Portals Tackle Duplicate Image Problem That Has Stalled Hundreds of Applications This Week

Hundreds of planning applications across London have been held up this week after a known software fault caused duplicate images — identical document scans submitted more than once — to clog case queues at borough-level planning portals, according to notices posted by several local authorities on their public-facing websites. The problem has been particularly acute in Southwark, Tower Hamlets, and Lewisham, where online submission volumes have risen sharply since the government's 2025 Planning and Infrastructure Bill pushed more of the process onto digital channels.

The fault matters now because the Starmer government's planning reform agenda is already under scrutiny over delivery speed. Councils have been told to process minor householder applications within eight weeks under current statutory timelines. Backlogs caused by technical failures eat directly into those windows, and applicants who miss decision deadlines can appeal on procedural grounds — an outcome that wastes council legal resources and further slows case throughput.

Where the Problem Is Hitting Hardest

In Southwark, the planning team at 160 Tooley Street posted a service notice on Monday, 30 June, warning applicants that cases submitted between 20 and 27 June may require resubmission if duplicate image files had been automatically attached by the upload interface. Tower Hamlets Council, which handles applications for areas including Whitechapel, Bethnal Green, and the Isle of Dogs, similarly flagged the issue on its planning portal, advising agents and self-submitters to check their application file lists before the case officer review stage begins.

The Greater London Authority's Planning Datahub, which aggregates borough-level data to feed into the Mayor's London Plan monitoring, confirmed in a brief technical bulletin dated 1 July that it was aware of duplicate file entries appearing in feeds from at least six boroughs. The GLA said it was working with its software provider to filter out the redundant records before they affected the central dataset. Lewisham's planning pages carried a similar advisory, specifically mentioning applications for extensions and loft conversions in the SE4 and SE13 postcode areas, where a spike in summer submissions is typical.

The underlying software used by many London boroughs is a widely deployed planning management system that has been the subject of upgrade work since early 2025. The duplicate-image fault appears to be linked to an automated file-copying routine introduced in a patch released in late May, though no authority has yet published a formal technical post-mortem.

What Applicants Should Do Now

Anyone who submitted a householder or minor commercial application in London between roughly 18 June and 1 July should log into their portal account and open the documents tab on their case. If the same floor plan, elevation drawing, or site photograph appears listed twice or more, they should contact their borough's planning support team by email — not phone — and request manual removal of the duplicate before the validation stage closes. Most boroughs complete initial validation within five working days of receipt.

For applications already validated, case officers at several boroughs have been authorised to proceed using the first-listed file version, which limits the practical delay for straightforward cases. However, applications involving listed buildings — including properties in conservation areas such as Blackheath Village, Highgate, and the Bankside riverside zone — require clean document sets as a matter of heritage compliance, meaning duplicate-image corrections there are not discretionary.

Planning agents operating across multiple London boroughs say the safest immediate step is to download a full case file summary from the portal, compare file names and sizes for identical entries, and flag any duplicates in writing before the eight-week statutory clock becomes a problem. The GLA's Planning Datahub has said it expects the central feed to be corrected by 7 July. Borough-level fixes are expected to follow within the same window, though individual councils may take longer depending on their IT support arrangements.

For homeowners in the middle of extensions or conversions, the practical advice is straightforward: check your application file this weekend, act by email on Monday morning, and keep a record of any correspondence in case you need to demonstrate good faith if timelines slip.