Unilateral undertakings vs Section 106 Agreements

April 7, 2026

Developers today face several difficulties with their projects, namely increasing construction costs, challenging financing conditions and significant planning delays. One of the biggest headaches for developers however can be Section 106 planning agreements. These agreements can impose tight obligations with lengthy negotiations, and many developers now seek guidance to relieve some of this pressure. This is where unilateral undertakings come in.

What is a unilateral undertaking?

Put simply, a unilateral undertaking is an agreement made solely by the Developer/ Landowner. They often avoid negotiation and don’t require the Local Planning Authority to sign off.

Differences between unilateral undertakings and Section 106 agreements

One of the biggest differences between these agreements is that Section 106 agreement requires both the council and the developer to enter into a binding deed. Unilateral undertakings however are essentially legal promises given exclusively by a developer where they commit to fulfilling specific planning obligations without the council being a party to the agreement. This allows the developer to draft the undertaking in a specific way that allows them to manage their risk and costs predictably.

Advantages of unilateral undertakings in planning law

Unilateral undertakings have several benefits such as quicker processing times due to the removal of negotiations with the council. This in turn can benefit both the developer and the council by allowing for planning permissions to be granted more quickly. Additionally, the developer’s intention to reduce costs is satisfied through these undertakings, with lower admin fees due to the removal of unnecessary and costly negotiations amongst parties. With the current economic climate, many developers are trying to stay clear of Section 106 agreements as a consequence of the significant financial and legal requirements they create, with the added risk of being bound by extra obligations demanded by the Council. It should be noted that developers will be unable to use unilateral undertakings in circumstances where multiple parties are required to commit to obligations under a planning agreement.

When can unilateral undertakings be used?

Unilateral undertakings fit into the planning process to secure straightforward planning obligations. They are often submitted along with the initial planning application. Developers are encouraged to submit the completed unilateral undertaking with the planning application to speed up the decision process as the Council can grant planning immediately from the undertaking being approved. There are also other circumstances where they can be submitted such as during the application determination process or (more commonly) when the developer wishes to overcome objections in connection to the planning appeals.

How can we help?

Here at Herrington Carmichael, our Solicitors can assist you with legal advice in connection unilateral undertakings and Section 106 matters, ensuring that all applications meet the regulatory requirements. Please contact us and a member of our team will assist you with your legal enquiries.

Thomas Joucan
Solicitor, Real Estate
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This reflects the law and market position at the date of publication and is written as a general guide. It does not contain definitive legal advice, which should be sought in relation to a specific matter.

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