Planning in Focus: Reforming Site Thresholds — Finally, a Size Guide That Matters

On 28 May 2025, the Department for Levelling Up, Housing and Communities (DLUHC) released the latest working paper in its ongoing saga of planning reform: “Reforming Site Thresholds.” Catchy? Not exactly. Vital? Potentially. A thrilling read? Only if you like spreadsheets with your urbanism.

At the heart of the proposal is a deceptively simple idea: perhaps we shouldn’t treat a 7-home cul-de-sac in Dorset the same way we do a 3,000-unit masterplan in Milton Keynes. Revolutionary, we know.

This working paper makes the case for reforming how planning policy interacts with site size. Why? Because developers, especially small and medium-sized ones, have been quietly (or not-so-quietly) screaming into the void for years: “It’s too hard to build houses.” In response, the government’s latest answer is: “What if we… adjusted the thresholds?”

Cue mild applause from planners and cautious optimism from SME developers—followed immediately by nervous glances toward the “consultation questions” section at the end.

Small, Medium, Large: Now Available in Planning

The headline proposal is to create a three-tiered system based on the number of homes or the size of the site. The thresholds are as follows:

• Minor Developments
  <10 homes or <0.5 hectares
  These are the bread and butter of SME builders—think disused garages, awkward corners of suburbia, or that one rogue back garden someone insists is a “development opportunity.”

• Medium Developments
  10–50 homes or 0.5–2 hectares
  Welcome to the awkward middle child of housing development. Too big for a relaxed chat with the planning officer, too small for economies of scale. These sites are often where ambition meets red tape.

• Major Developments
  >50 homes or >2 hectares
  This is the land of environmental impact assessments, legal battles, and the inevitable comment from a local resident that “this is totally inappropriate for the area.”

By categorising development into these tiers, the government hopes to create a more rational, proportionate system—where smaller sites face fewer hoops and hurdles, while the big boys still jump through their customary flaming rings of Section 106 negotiations and viability assessments.

Why Now? Or: How We Learned to Stop Ignoring SMEs

The UK has a housing delivery problem. (Breaking news, we know.)

But what’s less appreciated is that a large part of this issue stems from underutilised small and medium sites—the very ones that SME developers used to deliver in droves. In 1988, small builders were responsible for around 40% of new homes. Today, it’s barely 10%. What changed? It wasn’t the quality of bricks.

Instead, a mix of complexity, cost, and endless planning obligations has slowly squeezed out the smaller players, leaving large developers to pick up the slack (and then often drop it).

By reducing the burden on smaller sites—especially those with fewer than 10 units—the government hopes to reinvigorate SME involvement in housing delivery. In other words: give the little guys a break, and maybe we’ll actually build those 300,000 homes a year everyone keeps talking about like it’s a mythical prophecy.

Medium Sites: The Planning Bermuda Triangle

Interestingly, the paper gives particular attention to medium-sized sites, which often fall through the cracks of both local plans and developer business models. These plots are too complex for a casual sketch on the back of a napkin, but not profitable enough to withstand the delays and unpredictability of the full planning process.

The government wants to reframe how medium sites are treated—suggesting lighter-touch requirements where appropriate, and making them more attractive to both planners and developers.

This could be the sweet spot for future growth, especially in urban areas where large land assemblies are rare, and small sites are dwindling. It’s like the “Tesco Metro” of planning: convenient, local, and vaguely respectable.

The Devil, as Always, is in the Detail (and Probably a Footnote)

Of course, this is all still theoretical. The working paper is not a formal consultation, but it does include a generous helping of “Questions for Consideration” — a classic government move that says: We’re not promising anything, but do tell us what you think, in 1,200 words or less.

A few open questions worth pondering:

• What criteria should define each threshold?

• How should infrastructure contributions scale with site size?

• Can we simplify processes without creating loopholes big enough to drive a bulldozer through?

Planners, developers, and local authorities are all encouraged to respond by 9 July 2025. It’s an opportunity for stakeholders to help shape policy before the regulations are chiselled in statutory stone—or worse, PDF appendices.

Final Thoughts: A Step in the Right Direction, But Bring Hiking Boots

The “Reforming Site Thresholds” paper is not a silver bullet. But in a world where housing delivery often feels like trench warfare, even a slightly better map is welcome.

The proposal offers a refreshing bit of proportionality in a system that often treats all developments with the same suspicion and spreadsheet. If implemented wisely (and that’s a big “if”), this could re-balance the field, help SMEs get back in the game, and speed up delivery of much-needed homes.

Now all we need is a National Planning Policy Framework that doesn’t change every Thursday.

📄 Read the full paper here:
Reforming Site Thresholds – GOV.UK

📝 Deadline for feedback: 9 July 2025
🛠️ Working group status: Ongoing, with coffee.