Planning in Principle vs Outline vs Full Planning Permission: What’s the Difference?

Since it was introduced in 2018, Permission in Principle has quietly become one of the more common routes we see on sites brought to us by clients. More and more, we’re being asked to advise on land that already holds this consent and the first question is almost always the same: how does it actually compare to outline or full planning permission?

So here’s a quick breakdown of all three, and how they differ:

Permission in Principle (PiP)

The lightest-touch route. It confirms whether a site is suitable in principle for housing-led development, nothing more. No detailed drawings, no technical reports, just a red-line site plan and a short statement. It’s limited to minor residential schemes (up to 9 dwellings) and must be followed by a Technical Details Consent application before anything can be built.

Outline Planning Permission

A broader version of the same idea. It establishes that the principle of development is acceptable but can be used for any scale or type of development, residential or otherwise. Certain “reserved matters” (access, appearance, landscaping, layout, scale) are deferred and approved later, usually within 3 years.

Full Planning Permission

Everything upfront. Detailed drawings, technical reports, and design specifics are all submitted and assessed in one go. Once granted, you can move straight to discharging conditions and starting on site.

The core difference comes down to how much detail you commit to now vs later and that has real implications for speed, cost, and risk.

Need certainty fast on a small site? PiP might work.
Bigger or more complex scheme, but want to lock in the principle before investing in detailed design? Outline could be the answer.
Ready to build and want a clean, single-stage route? Go full.

Choosing the right route can save months (and a fair bit of budget), which is exactly the kind of decision we help clients navigate every day.