What Is Suitable Alternative Natural Greenspace (SANG)?

12 hours ago
3 min read

If you’re promoting or delivering housing in parts of the South East, you will eventually run into SANG.

It isn’t “nice to have” open space. It is a legally-driven mitigation tool used to ensure residential development does not increase recreational pressure on protected habitats, most commonly Special Protection Areas (SPAs) and Special Areas of Conservation (SACs), under the Habitats Regulations and the Habitats Regulations Assessment (HRA) process.

The key issue is that the planning question is not whether new housing is acceptable in principle, but whether its impacts on protected sites can be avoided or mitigated with certainty.

What is a SANG?

A Suitable Alternative Natural Greenspace (SANG) is a high-quality recreational greenspace intended to attract residents (and dog walkers) away from sensitive designated sites, reducing visitor pressure on those habitats. Councils describe SANGs as enhanced or managed open spaces with features such as paths, signage, car parking (often), bins and seating designed to be appealing day-to-day destinations.

SANG is most widely associated with mitigation for the Thames Basin Heaths SPA (Surrey, Berkshire and Hampshire), where the underlying issue is disturbance to ground-nesting birds from recreational activity.

Where SANG typically applies

SANG requirements are not universal across England; they tend to be place-specific and secured through local avoidance and mitigation strategies, often set out in an SPD.

In practice, you most often see SANG in authorities around the Thames Basin Heaths SPA e.g. Wokingham, Bracknell Forest, Runnymede, Windsor & Maidenhead and in other areas where a similar recreational-pressure issue needs a defined mitigation mechanism.

When does a development need SANG?

Most SANG-triggering policies are written around:

Residential development (net new dwellings / net new bedrooms), because that’s what generates new recreational trips; and
A defined “zone of influence” around the protected site (often a distance-based buffer).

For example, Windsor & Maidenhead states that net new dwellings within 5km of the Thames Basin Heaths SPA require mitigation, delivered through a two-pronged approach: SANG + SAMM.

This is why feasibility and site strategy work should always include an early habitats screen: the mitigation route can materially affect land-take, layout, programme and cost.

SANG and SAMM: what’s the difference?

SANG is only one part of the wider mitigation toolkit.

SANG deals with the “where do people go?” question providing alternative places to walk and recreate.
SAMM (Strategic Access Management and Monitoring) deals with strategic management, such as wardening, monitoring and education measures across the protected site and its access points.

The practical implication is that even where a scheme can provide bespoke SANG, SAMM contributions may still apply, depending on the authority’s approach.

How SANG is delivered: on-site, off-site, or tariff-funded

There are usually two delivery routes.

1) Council / partnership SANG (tariff-funded): Many authorities operate a SANG tariff (often alongside a SAMM tariff). Developers contribute financially, and the authority (or a partnership) delivers and manages a network of SANG sites. This is common for small to mid-sized schemes where delivering land directly is unrealistic.

2) Bespoke SANG (provided by the developer): For larger schemes, a developer may deliver bespoke SANG, typically secured through a Section 106 obligation with land set aside and laid out to the required standard, access and facilities delivered before occupation triggers, and management “in perpetuity” (often via a management company and commuted sums).

What emerges is a straightforward strategic choice: pay the tariff and de-risk delivery, or provide land and control the on-site solution, but accept the land-take and long-term obligations.

What developers should do early

SANG is easiest to manage when it is treated as a site strategy constraint (not a late-stage planning condition).

A practical early checklist:

Confirm the zone of influence for the relevant SPA/SAC and whether the proposal creates a net increase in dwellings/bedrooms.
Establish the authority’s mitigation route (tariff, bespoke SANG, or both).
Model land-take and layout implications if bespoke SANG is likely.
Agree the legal mechanism early (normally S106) and draft heads of terms that lock down triggers, maintenance, and monitoring.
Programme realistically: habitats mitigation is often a gating issue for determination, committee, and completion.

Why this matters commercially

The risk is that SANG is treated as “just another contribution” and priced late. In reality, it can affect:

Developable area / density (particularly where on-site SANG is needed),
residential mix (bedroom-led tariffs),
timing of first occupation (mitigation delivery triggers),
land value and bid strategy, and
deal certainty (because HRA compliance is a legal test, not a policy preference).
Handled early, SANG is usually a solvable constraint. Left late, it becomes a consent-critical risk.