Planning Conditions and Section 278/38 Agreements: Getting the Access Delivered
Planning conditions, S278 and S38 agreements for delivering highway access — taking into account the August 2026 NPPF's new DM6 conditions policy.
PLANNING APPLICATIONS
Andrew Ransome
9/3/20265 min read
Winning planning permission for a scheme with a sound highways case is only half the job. The access, the visibility splays, the road works, and any new streets still need to be built and adopted.
That job falls to two things working together:
Planning conditions attached to the permission itself
Separate highway agreements sitting alongside it — Section 278 and Section 38
This article covers how conditions secure highways outcomes, why some are drafted in a distinctive negative form, and how S278 and S38 agreements actually deliver the infrastructure on the ground — updated to reflect the August 2026 NPPF, which now sets out the test for planning conditions as a national decision-making policy in its own right.
What makes a condition lawful in the first place
The underlying legal test comes from Newbury District Council v Secretary of State for the Environment [1981] AC 578. A condition must:
Be imposed for a planning purpose, not an ulterior one
Fairly and reasonably relate to the permitted development
Not be so unreasonable that no reasonable authority could have imposed it
The August 2026 NPPF now restates this test directly, through national decision-making policy DM6: Use of planning conditions and obligations. Conditions should only be attached where they are:
Necessary to make the development acceptable in planning terms
Relevant to the development and to planning considerations generally
Sufficiently precise to be capable of being complied with and enforced
Reasonable in all other respects
DM6 also sets two limits that matter directly for highways casework. Conditions should not be used to:
Require payments of money, or
Require land to be formally given up to another party — including highways to the local highway authority
This is exactly why land transfer and adoption of new highway infrastructure has to go through a separate legal agreement (S278 or S38), never through a condition alone.
DM6 also confirms that national model conditions should be used where relevant, unless there's a strong reason to depart from them.
Where a highways condition strays beyond this — requiring more than the development makes necessary, or duplicating a S278 obligation — there's a proper basis to challenge it, whether through negotiation, at appeal, or by judicial review in the most extreme cases.
Grampian conditions: promising something you can't yet guarantee
A Grampian condition is negatively worded.
Instead of requiring specified works, it blocks development from starting, or from being occupied, until something else has happened — typically:
Completion of off-site highway works
Entry into a S278 agreement
Making of a Traffic Regulation Order
The principle comes from British Railways Board v Secretary of State for the Environment [1994] 1 WLR 631, named after an earlier Grampian Regional Council case. The House of Lords confirmed that this kind of condition can be lawful even where the specified event is genuinely uncertain — for example, where it depends on land the applicant doesn't yet own, or on a highway authority agreeing to something not yet formally committed.
The key test: is there a reasonable prospect of the condition being met within the life of the permission?
If yes, the condition is likely lawful, even if fulfilment sits outside the applicant's direct control.
If not — if the specified event is effectively impossible — the condition, and potentially the permission itself, becomes vulnerable to challenge as an unlawful device.
This is why deliverability matters so much.
An obligation resting on a third party — the highway authority, a landowner, National Highways — needs a realistic, evidenced prospect behind it, not just an aspiration. Push back hard on Grampian conditions that lock a scheme into an outcome genuinely outside anyone's control.
Pre-commencement conditions: proceed with caution
These conditions stop even site clearance or enabling works starting until they're discharged.
Sometimes that's genuinely necessary — where an access has to be built, or visibility splays created, before anything else happens safely.
But they carry real costs:
Can hold up a start on site for months
Direct impact on finance costs and contractor mobilisation
Risk to deadlines tied to implementing the permission
DM6 now directly discourages this practice: conditions requiring discharge before development commences should be avoided, unless there is a clear justification.
Applications to discharge conditions should also be dealt with in a timely manner, to avoid unnecessary delay.
This sits alongside the existing statutory requirement — in place since 2018 — for local planning authorities to get an applicant's written agreement before imposing a pre-commencement condition.
Use that requirement.
Ask whether each pre-commencement highways condition genuinely needs to bite before any development begins, or whether it could apply at a later trigger point instead — first occupation, or the start of a specific phase — without losing the underlying highway safety rationale.
Section 278: paying for and delivering off-site works
Where a scheme needs works to the existing public highway — a new junction, an upgraded footway, a signalised crossing — these are secured through a Section 278 agreement, made under Section 278 of the Highways Act 1980.
A separate legal agreement between developer and highway authority
Distinct from the planning permission itself
The developer funds and constructs the works
The highway authority formally adopts and maintains them
Timing matters. A S278 agreement takes time: technical drawings need approval, a commuted sum for future maintenance often has to be agreed, and the highway authority's internal processes can be slow.
Where occupation is tied to a Grampian condition requiring the S278 agreement to be in place, start the process early — in parallel with discharging other conditions, not as an afterthought.
Section 38: adopting new streets
Where a development creates entirely new streets — as most residential schemes of any scale do — these are typically transferred to the highway authority through a Section 38 agreement, made under Section 38 of the Highways Act 1980.
The developer builds the streets to the highway authority's specification
Formally offered up for adoption once complete and any defects period has passed
Different from S278: it deals with new streets within the site, not the existing public highway
The August 2026 NPPF's TR4: Street design, access and parking alongside N3: Trees in new development now sit alongside this.
New streets should generally be tree-lined, unless there's strong reason otherwise, and street design should prioritise walking, wheeling, cycling and public transport access ahead of vehicles.
These design requirements can influence street widths, materials, drainage and geometry — all of which feed directly into adoptable standard.
Get this right early:
Engage with the highway authority's technical approval process at design stage, not just at application stage
Streets built below adoptable standard, or without an agreement in place, can end up permanently privately maintained
That creates long-term liability for a management company or the eventual residents
Bringing it together
Conditions, Grampian wording, S278 and S38 agreements are never just administrative formalities to tidy up after permission is granted. Each is a genuine point of risk and negotiation, capable of:
Delaying a start on site
Adding unplanned cost
In the worst cases, leaving a permission incapable of being lawfully implemented
The August 2026 NPPF's TR6: Assessing transport impacts reinforces this from the other direction. Development should be refused where it would have a severe adverse impact on the transport network, or an unacceptable impact on highway safety — taking mitigation into account.
Getting the conditions and agreements right isn't a side issue; it's part of how that severe-impact test gets satisfied in practice.
Understanding how these mechanisms work — and engaging with the highway authority on substance early, not late — is one of the most effective ways to protect a hard-won planning permission all the way through to a completed, adopted, functioning scheme.
Andrew Ransome MRTPI - Email: andrew@andrewransome.co.uk
About me
Andrew Ransome is a Planning Director and a Chartered Member of the Royal Town Planning Institute (RTPI), with more than two decades of experience in town planning.
He specialises in delivering strategic planning solutions for complex developments across both rural and urban environments, helping clients navigate planning challenges and unlock development opportunities. Connect with Andrew on Linkedin.
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Get in touch for planning advice: Email: andrew@andrewransome.co.uk
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