Commencement notices and completion notices explained

The commencement notice planning requirement introduced by the Levelling-up and Regeneration Act 2023 obliges a developer to tell the local planning authority, in advance, the date on which development will begin. Alongside it sit development progress reports for prescribed larger developments and a reworked completion notice regime that lets an authority bring an unfinished permission to an end. As at October 2026 these provisions depend on commencement regulations and on secondary legislation setting out which developments are caught, so check the commencement status and the current section numbering on legislation.gov.uk before advising anyone.

What the 2023 Act introduced

Part 3 of the Levelling-up and Regeneration Act 2023 inserted a group of new provisions into the Town and Country Planning Act 1990 dealing with what happens after permission is granted. Three are relevant here.

A commencement notice obligation: the person who will carry out the development must notify the authority of the date development is expected to begin, and notify again if that date changes. The Act also creates an offence of failing to comply.

A development progress report obligation for prescribed developments, requiring periodic reporting on build-out against the notified start.

Amendments to the completion notice power, which has existed in the 1990 Act for decades but was rarely used because it required confirmation by the Secretary of State. The 2023 Act reworked that mechanism.

The policy purpose behind all three is build-out. Authorities have long complained that they cannot tell whether a permission has started or stalled, and the data that commencement notices and progress reports generate is intended to feed into monitoring and into decisions about future allocations.

Who must serve a notice and when

The obligation falls on the person carrying out the development rather than on the original applicant, which matters where a permission has been sold or where a developer is building out under an option. Get that allocation right in the development agreement, because an obligation that nobody has taken responsibility for is one nobody serves.

Do not confuse any of this with the commencement notice already required under the Community Infrastructure Levy Regulations 2010. That notice is a separate, long-standing requirement, it goes to the collecting authority rather than the planning department, and failure to serve it before starting a chargeable development costs you any relief or exemption claimed, with a surcharge on top. The two notices coexist and you will need both. The levy side is dealt with in our note on commencement notices and the CIL amendment regulations.

What a completion notice does

A completion notice states that the planning permission will cease to have effect at the end of a period specified in the notice, which cannot be less than 12 months from service. If the development is not completed within that period, the permission lapses to the extent that it has not been implemented.

That has a brutal consequence on a partially built site. Anything lawfully completed stays lawful. Anything not yet built loses its permission, so finishing the scheme requires a fresh application against whatever policy and whatever levy rates then apply. On a site where the plan has moved on, or where the biodiversity and sustainability requirements have tightened, that is a serious exposure.

Historically the power was a dead letter because of the confirmation requirement. The 2023 Act changed the procedure, and the practical question is how willing authorities will be to use it. The honest answer as at October 2026 is that use has been limited and the deterrent effect is probably greater than the enforcement effect, but a developer holding a half-built site through a long pause should not rely on that.

How time limits on permissions interact

The underlying time limits are unchanged. A full permission must be begun within three years of grant under section 91 of the 1990 Act, unless the permission specifies otherwise. An outline permission requires reserved matters applications within three years and the development to begin within two years of the final approval under section 92.

Development is begun when a material operation is carried out, which section 56(4) defines to include work of construction in the course of erecting a building, digging a trench for foundations, laying underground mains or pipes, road construction and certain demolition. A token start is lawful if it is in fact a material operation on the permitted scheme and any pre-commencement conditions have been discharged.

Two traps follow. A start made without discharging a pre-commencement condition may be unlawful, and in some circumstances cannot be relied on as implementation at all. And the deemed biodiversity gain condition now attaches to most permissions, so a biodiversity gain plan has to be approved before development begins, as set out in our piece on the biodiversity gain condition on every permission.

Consequences of failing to notify

For the commencement notice regime, the Act creates an offence, and the penalty will be set out in the provisions once in force and in any regulations. For the levy notice, the consequence is financial and automatic rather than criminal.

The quieter consequence is evidential. An authority with no commencement notice on file may simply not accept that development began when you say it did, and the burden of proving implementation sits with the person asserting it. Where a permission is approaching its expiry date, that burden is the whole ballgame.

Illustrative example: a 60-unit site where permission expires in March. Groundworks start in February with a trench dug for the first plot's foundations. No commencement notice is served to the planning authority, and the levy commencement notice is served three days after the trench is dug, which loses the self-build relief claimed on two plots. In July the authority queries whether the permission was implemented. The developer has a contractor invoice and six photographs with no metadata. The scenario is illustrative, and the lesson is about record keeping rather than about the law.

Record keeping for implementation evidence

Build a short implementation file for every site and close it the week work starts.

1. Copies of both commencement notices, with proof of service and the dates.
2. Written confirmation that every pre-commencement condition has been discharged, with the decision notices.
3. The approved biodiversity gain plan where one is required.
4. Dated and geolocated photographs of the material operation, taken before, during and after.
5. The contractor's instruction, the invoice and the site diary entry.
6. A note identifying which drawing and which part of the permission the operation relates to.

A Construction Management Plan submitted and approved before work starts is often the condition that catches people out, because it is routinely imposed as pre-commencement and routinely left until the contractor is appointed.

Practical steps for a developer

Allocate the notice obligations in the development agreement by name and role. Diary the permission expiry date, the two notice dates and the pre-commencement condition discharge dates together. Serve both commencement notices, to both recipients, in writing, and keep the proof. Assume a progress report obligation will apply if your scheme is large, and set up the monitoring data collection at the outset rather than retrofitting it.

As at October 2026 the source material is the Levelling-up and Regeneration Act 2023 as amended, the Town and Country Planning Act 1990 as amended by it, and the Community Infrastructure Levy Regulations 2010. Commencement of individual provisions is by regulations, so verify the position on legislation.gov.uk at the point you rely on it, and follow reform news on the planning law timeline.

Enter your postcode on PlanScope to see which pre-commencement documents a scheme in your area is likely to need.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.