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Eight weeks down to four. That is the change in processing time for routine householder planning applications reported in early testing of the PlanAssist AI planning tool, according to Propertymark’s 5 November 2026 briefing on the government rollout [1]. For London homeowners planning an extension, loft conversion or basement, a faster planning decision sounds like pure good news. For their neighbours, it means the Party Wall etc. Act 1996 timetable arrives sooner than many expect.
Key Takeaways
- PlanAssist helps planning officers produce initial assessments of routine applications such as extensions, loft conversions and conservatories; officers still make the final decision [1].
- Early testing cut time spent on key planning tasks by 58% and halved processing time for routine applications from eight weeks to four [1].
- The tool was tested with Camden, Barnet and Dorset councils, is expanding to 12 more, and is intended to reach every council in England by the end of 2027 [1].
- Planning permission and party wall consent are separate. A faster planning decision does not shorten the statutory notice periods under the Party Wall Act.
- Serving party wall notices early, and agreeing a schedule of condition, protects both the building owner and the adjoining owner.
What the PlanAssist AI Planning Tool Does
PlanAssist is a government AI tool designed to help planning officers process routine applications faster. It targets householder projects such as extensions, loft conversions and conservatories, as well as small business property improvements [1].
The tool combines three inputs to produce an initial assessment [1]:
- The planning application itself.
- Local planning policies.
- Site constraints, such as conservation area status.
Propertymark quotes the government position that “qualified planning officers will remain responsible for reviewing assessments and making final decisions” [1]. The AI drafts; a human decides.
PlanAssist AI Planning Tool Rollout: Dates and Councils
Alongside the rollout, the government has renewed the National Scheme of Delegation and recruited 420 additional planners, in support of its target of 1.5 million homes this Parliament [1]. Two of the three pilot councils, Camden and Barnet, are London boroughs, so parts of the capital are already seeing the effect.
Propertymark welcomed faster processing for smaller applications but questioned whether similar gains can be achieved on larger developments, and pointed to staffing shortages and financial pressures at local planning authorities [1]. It also notes that the Future Homes and Buildings Standards for new homes take effect from March 2027 [1].
Why Faster Planning Means Earlier Party Wall Notices
The PlanAssist AI planning tool changes when a homeowner can start building. It does not change the Party Wall etc. Act 1996. The two processes run in parallel, and the Act’s notice periods are fixed by statute:
- Works to a party wall or party structure (for example cutting in beams for a loft conversion or raising a shared wall): notice must be served at least two months before the work starts.
- Excavation within 3 metres or 6 metres of a neighbour’s foundations, depending on depth (typical for rear extensions and basements): notice must be served at least one month before.
- New walls on the line of junction: notice must be served at least one month before.
Under the old eight-week planning timeline, a homeowner who served notices on the day of submission would usually have the two-month period run alongside the planning decision. With a four-week decision, the planning permission can arrive before the party wall notice period has ended. Builders are then booked, and the neighbour’s reply becomes the critical path.
A faster planning decision is only useful if the party wall process keeps pace with it. Serve notices at the design stage, not after the approval letter arrives.
What Adjoining Owners Should Do When a Notice Arrives
Neighbours receiving a party wall notice have three options:
- Consent in writing within 14 days. Even with consent, a schedule of condition is strongly advisable.
- Dissent and appoint a surveyor. The parties may agree a single “agreed surveyor” or each appoint their own.
- Do nothing. After 14 days the notice is deemed dissented, and a dispute arises that surveyors must resolve.
The adjoining owner’s reasonable surveyor costs are normally paid by the building owner. A schedule of condition records cracks, finishes and defects before work starts, so any later damage can be fairly assessed.
What This Means for London Homeowners
For a building owner, the practical sequence in late 2026 is:
- Identify which neighbours are affected as soon as drawings exist.
- Serve the correct notices early so the two-month or one-month period runs during, not after, the planning process.
- Appoint a party wall surveyor to prepare the notices, agree the award and record the schedule of condition.
- Keep neighbours informed, which reduces the chance of dissent.
A party wall surveyor can serve valid notices, act as agreed surveyor for both sides, prepare the award and schedule of condition, and advise where excavation depth brings the 6-metre rule into play.
FAQ
Does PlanAssist approve my extension automatically?
No. It produces an initial assessment. Propertymark reports that qualified planning officers remain responsible for the final decision [1].
If planning is granted in four weeks, can I start work straight away?
Not if the work is notifiable under the Party Wall Act. The statutory notice periods of one or two months still apply, and work cannot lawfully start until consent is given or an award is made.
Do I need a party wall surveyor for a loft conversion?
If the loft conversion involves cutting into or raising a party wall, notice is required. A surveyor is needed if the neighbour dissents or fails to respond within 14 days.
Which London councils use PlanAssist now?
Camden and Barnet were pilot councils, with Dorset, and the tool is expanding to 12 further councils ahead of national rollout by the end of 2027 [1].
Conclusion
The PlanAssist AI planning tool is likely to shorten the wait for permission on extensions and loft conversions across London as the rollout continues through 2027 [1]. The party wall timetable will not shrink with it. Homeowners who serve notices at the design stage, and neighbours who respond promptly and secure a schedule of condition, will be the ones who benefit from the speed.
Next steps: check whether your project touches a party wall or involves excavation near a neighbour, serve notices early, and appoint a party wall surveyor before the planning decision lands.
References
- Propertymark, “AI tool to speed up planning decisions for homeowners”, 5 November 2026. propertymark.co.uk.