New NPPF buffer raises the bar for councils on outdated housing plans

A change to national planning policy that makes it harder for councils to rely on outdated housing plans has come into effect, following an 18-month transition period since the wider National Planning Policy Framework began.

The problem it addresses is familiar to planning professionals. Local housing need in England is calculated using a standard method set out in national guidance, the figures from which have climbed sharply in many areas since the method was last updated. A significant number of councils, however, are still working to older local plans that set housing targets well below what the area now needs on paper.

Rather than force every affected council to rewrite its plan overnight, any authority whose adopted housing requirement sits at 80 per cent or less of its current local housing need figure must apply an extra 20 per cent buffer to its five-year housing land supply – effectively requiring six years of supply rather than five.

What the buffer requires

Authorities caught by the rule must demonstrate housing land supply covering an extra year, on top of the usual five.

It applies at the decision-making stage – planning applications and appeals – rather than forcing an immediate rewrite of the local plan itself.

This new buffer sits alongside, not on top of, the existing 20 per cent buffer already applied to councils scoring below 85 per cent on the Housing Delivery Test, so affected councils are not penalised twice.

Where the pressure is being felt

Recent analysis has identified 157 local planning authorities and plan areas across England currently unable to demonstrate a five-year housing land supply. Some of these will have looked comfortable enough under the old calculation, only to fall short once the tougher six-year test applies. For councils sitting on old, lower housing targets, there is now a considerably sharper incentive to adopt an up-to-date local plan.

What this means for developers and landowners

Where a council cannot demonstrate the required supply, including the new buffer, the policies most relevant to determining an application are treated as out of date, and the presumption in favour of sustainable development strengthens accordingly. For site promoters and developers with schemes in the areas affected, this may improve the prospects of marginal applications and appeals through the second half of 2026, particularly where a council's housing trajectory already leans on delayed strategic sites or optimistic delivery assumptions.

Councils facing the sharpest exposure now have a choice to make: accelerate work on a new local plan, or risk more housing coming forward outside the plan-led system than they would like.

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