Unilateral undertakings: when to use one instead of an agreement

A unilateral undertaking is a planning obligation given by the landowner alone. Section 106 of the Town and Country Planning Act 1990 allows an obligation to be entered into by agreement with the local planning authority or by any person interested in the land, and the second route produces a deed the council never signs. For a small scheme with a simple obligation, or for an appeal where the council will not negotiate, that difference turns a three-month legal exercise into a two-week one.

What a unilateral undertaking is

It is a deed. The landowner covenants to do or not do something, the deed states that the covenant is a planning obligation under section 106, and it identifies the land, the person giving the obligation and their interest in the land, and the authority by whom it is enforceable.

Once given, it binds the land. The authority can enforce it against the person who gave it and against anyone who later acquires an interest, which is what makes it useful to a council even though the council was not a party to it.

Everyone with an interest in the land should be a party. A freeholder alone is not enough where there is a leaseholder, and a mortgagee's consent should be obtained so that the obligation is not defeated if the lender takes possession. This is the point at which unilateral undertakings most often fail in practice, and it is a title question rather than a planning one.

Where it is faster than a bilateral agreement

A section 106 agreement needs two sets of solicitors, a council legal department with a queue, engrossment, sealing and completion. Three months is common and longer is not unusual.

A unilateral undertaking is drafted by one side. The council will still want to review it, and will usually charge for doing so, but there is no negotiation of mutual covenants and no waiting for a second signature.

That makes it well suited to:

• A single financial contribution with a clear trigger.
• A restriction on the use or occupation of a building, such as a self-build or holiday occupancy condition that cannot sensibly be a planning condition.
• Removal of permitted development rights on a new dwelling.
• A covenant not to implement an earlier permission on the same land.
• A small affordable housing obligation on a rural exception site.

It is less suited to a package of obligations with phased triggers, review mechanisms and shared definitions, where the drafting benefits from both sides working through it.

Its use at appeal

This is where unilateral undertakings do most of their work. Where a scheme is refused and the council would have required an obligation, the appellant can put a unilateral undertaking before the inspector so the appeal is not lost on a matter that could have been resolved.

The inspector will consider whether the obligation meets the tests in regulation 122 of the Community Infrastructure Levy Regulations 2010: necessary to make the development acceptable in planning terms, directly related to the development, and fairly and reasonably related to it in scale and kind. If it does not, the undertaking is simply given no weight, and the appeal is decided as if it did not exist.

Submit it in executed form by the deadline the Planning Inspectorate sets, not in draft. An unexecuted draft is worth very little, and there is no opportunity to complete it afterwards. Send the council a copy early enough for them to comment, because an authority that says the drafting does not work will carry weight with the inspector even though it is not a party.

Where the obligation is offered in the alternative, for example a contribution payable only if the inspector concludes it is necessary, say so expressly in the deed. Inspectors are used to that structure.

The limits: no reciprocity

The council cannot promise anything in a unilateral undertaking, because it is not a party to it. Three consequences follow.

There is no covenant to spend a contribution on anything in particular. You are paying into the authority's hands on the terms you have set, and if you want the money tied to a named project, that needs a bilateral agreement.

There is no repayment obligation for unspent sums. In a negotiated agreement you can ask for money to be returned if it has not been applied within a period. In a unilateral undertaking you cannot, because the promise would have to come from the council.

There is no council agreement on interpretation. Where a trigger is ambiguous, you find out what the authority thinks it means at the point they try to enforce it.

You can mitigate the first two by drafting carefully: define the purpose of the contribution in the deed so that its application is at least described, set the trigger so that payment falls due as late as the authority will accept, and index from a clearly stated date.

Drafting so the obligations bite

A deed that does not work is worse than no deed, because it creates the appearance of a solution while leaving the planning problem unresolved.

1. Identify the land by reference to a plan attached to the deed, with the plan matching the application red line.
2. Name every person with a legal interest, and obtain mortgagee consent where there is a charge.
3. Define each obligation with a single unambiguous trigger, such as first occupation of the tenth dwelling.
4. State the index and its base date for any monetary obligation.
5. State expressly that the obligation is a planning obligation under section 106 and identify the enforcing authority.
6. Include a provision that the obligations cease to have effect if the permission is not implemented or lapses.
7. Send the executed deed to the authority and ask them to confirm registration as a local land charge.

Point six is the one applicants forget. Without it, an obligation can sit on the title after a permission has expired.

When a council will refuse to accept one

Authorities are entitled to say a unilateral undertaking is inadequate, and they do so for predictable reasons: it does not bind all the interests in the land, the triggers are unclear, it omits monitoring provisions the council expects, or the obligations offered are not the ones the authority considers necessary.

Some authorities also prefer bilateral agreements as a matter of policy for anything beyond a single payment, and while that is not a legal objection, it is a practical one during an application. At appeal, the inspector rather than the authority decides what weight to give the deed.

Where you expect to use a unilateral undertaking, say so in the Planning Statement submitted with the application, set out the obligations offered and attach a draft. That converts a late scramble into a scheduled task. Where affordable housing is involved, the mechanism should also be described in the Affordable Housing Statement, because the delivery route matters as much as the quantum. The full list of supporting documents sets out what else a scheme of that scale usually needs.

This is general guidance, not legal advice. A unilateral undertaking is a deed with lasting effects on your title, so instruct a solicitor and check the position with your local planning authority before relying on it.

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