Getting the CIL forms wrong, and what it costs
CIL mistakes are procedural. Miss the commencement notice and you can lose an exemption, lose instalments and pick up a surcharge, with no discretion to put it right.
The costly CIL forms mistakes are procedural, not arithmetical. The Community Infrastructure Levy Regulations 2010 make relief and instalment rights conditional on serving the right notice at the right time, and they give the collecting authority no discretion to forgive a late one. A self-builder who starts work the week before posting a commencement notice can lose an exemption worth tens of thousands of pounds and pick up a surcharge on top.
This is the least forgiving part of the planning system. Treat the forms as a sequence with hard gates rather than paperwork to catch up on.
The sequence of forms and what triggers each
The standard forms are numbered and published on the Planning Portal. The order they are served in matters more than their content.
- The additional information form goes in with the planning application, giving floor areas and existing building details so the authority can calculate the charge.
- After permission is granted, the authority issues a liability notice stating the chargeable amount. Check it.
- Assumption of liability is served by whoever will pay, before commencement.
- Any claim for exemption or relief, whether self-build, residential annex, residential extension, charitable or social housing, is submitted and must be granted before commencement.
- A commencement notice is served on the authority, and it must be received before work starts.
- The authority then issues a demand notice setting out what is payable and when.
A notice of chargeable development is needed instead of steps one and two where development proceeds under permitted development or a general consent rather than a planning permission. That case catches people out on prior approvals and larger householder extensions.
Assumption of liability before starting work
Assumption of liability is the form that says who pays. If nobody assumes liability, the charge falls on the landowner by default and the Regulations provide for a surcharge on top.
Two practical points. The person assuming liability should be the person who will actually be there at commencement and completion, which on a self-build is the owner rather than the builder. And where the property changes hands mid-project, liability has to be transferred using the transfer form before commencement of the relevant part, not settled in the conveyancing and left unreported.
Assumed liability can be withdrawn, but only before commencement. After commencement the position is fixed.
The commencement notice and why it matters most
Of all the CIL forms, this one causes the most damage when it is missed.
The commencement notice tells the authority the date development will start. It has to be received by the collecting authority before that date. There is no late filing, no reasonable excuse provision and no discretion.
Two consequences follow from failure. The right to pay by instalments is lost, so the whole charge becomes payable immediately even where the authority's instalment policy would have spread it over a year or more. And a surcharge is imposed, calculated under the Regulations as a proportion of the chargeable amount subject to a cash cap, so check the current percentages and caps in the Regulations rather than assuming a figure.
The date of commencement is not a matter of opinion. Section 56 of the Town and Country Planning Act 1990 defines the material operations that constitute a start, and they include digging foundation trenches, laying underground mains or pipes, constructing a road, and work of demolition. A digger clearing the site and grubbing out a foundation counts. Scaffolding and a site hoarding generally do not, but the line is close enough that the safe course is to serve the notice before anything happens on site.
On a phased permission each phase is a separate chargeable development with its own commencement notice. Serving one notice for the whole scheme and then starting phase two eighteen months later is a common and expensive error.
Surcharges, interest and the loss of instalments
The Regulations set out a series of surcharges for procedural failures: for failing to assume liability, for failing to serve a commencement notice, for failing to comply with an information notice, for disqualifying events affecting relief, and for late payment, with late payment interest running as well.
The pattern to understand is cumulative. A missed commencement notice on a self-build can produce the loss of the exemption, the loss of instalments, a commencement notice surcharge and late payment surcharges accruing while the dispute runs. The bill is not the charge plus a penalty. It is the charge, brought forward, with several additions.
Instalment policies are set locally and published by the collecting authority, so read the policy that applies to your site. Some allow payment over two or three tranches within a year of commencement, others are more generous on larger schemes. That policy is worthless if the commencement notice is late.
Appeals and reviews, and their deadlines
The Regulations provide several routes, and each has its own short deadline and its own decision-maker.
A request for review of the chargeable amount goes to the collecting authority itself, and is the right route where the calculation has used the wrong floor area or failed to deduct an existing building. An appeal on the chargeable amount and on the apportionment of liability between owners goes to the Valuation Office Agency. Appeals against surcharges, against a deemed commencement date determined by the authority, and against decisions on exemptions and relief go to the Planning Inspectorate. The relevant provisions sit at regulations 113 to 119.
Three things to know about all of them. The deadlines are counted in days from the date of the notice, not from when you opened the envelope. Most routes require that any charge already demanded is dealt with in parallel, because an appeal does not automatically suspend payment. And an appeal against a surcharge for a late commencement notice will not succeed on the grounds that the failure was an oversight.
Where the argument is that the floor area is wrong, gather the evidence before requesting review: measured survey, the existing building's lawful use and whether it was in use for the qualifying period, and the treatment of any part being demolished. The deduction for an existing in-use building is where most successful reviews are won.
Records to keep from the outset
Keep a single CIL file from the day the application is submitted, containing the additional information form as submitted, the liability notice, the assumption of liability with proof of receipt, any relief claim and the authority's written grant of it, the commencement notice with proof of receipt, the demand notice, and payment receipts.
Proof of receipt is the part people skip. Email submission with a read receipt or an acknowledgement from the authority, or recorded delivery, is worth the effort. A dispute about whether a commencement notice was served comes down to evidence, and a printout of an unsent draft is not evidence.
Diary the dates as well. The date relief was granted, the date development started, instalment due dates and, where a self-build or annex exemption applies, the end of the post-completion period during which a disqualifying event can trigger a clawback.
A checklist for a small site
Before anyone goes on site, confirm all of the following in writing: the liability notice has been received and the chargeable amount checked against your own floor area calculation, liability has been assumed by the right person, any exemption has been claimed and granted, and the commencement notice has been served and acknowledged with the correct date.
After commencement, confirm the demand notice matches the instalment policy, and put the payment dates in the programme alongside the build milestones.
The sequencing of the individual forms is set out in more detail in the note on which CIL notice to send and when, and the wider financial consequences of building first and applying later are covered in the note on the cost of retrospective development. Other budget lines that are routinely underestimated are set out in the note on utility connection costs.
If you are pricing the document side of a project rather than the levy, see PlanScope pricing for one free report, £50 per report, or Professional for unlimited reports.
This is general guidance, not legal advice; check the position with your collecting authority or a qualified professional before relying on it, and check the current text of the Regulations for surcharge rates and time limits. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What happens if I miss the commencement notice?
The right to pay by instalments is lost, so the whole charge becomes payable immediately, and a surcharge is imposed under the Regulations as a proportion of the chargeable amount subject to a cash cap. There is no late filing provision and no reasonable excuse defence. Serve the notice before anything happens on site.
Can an exemption be claimed after work starts?
No. Any claim for self-build, residential annex, residential extension, charitable or social housing relief must be submitted and granted before commencement. The Regulations give the collecting authority no discretion to accept a late claim, however sympathetic the circumstances. This is the single most expensive mistake in the levy regime.
What counts as commencement?
The material operations defined in section 56 of the Town and Country Planning Act 1990, which include digging foundation trenches, laying underground mains or pipes, constructing a road and work of demolition. Site clearance that grubs out a foundation counts. Scaffolding and hoarding generally do not, but the margin is narrow enough that serving early is the safe course.
Where do I appeal a CIL charge?
A review of the chargeable amount goes to the collecting authority. Appeals on the chargeable amount and on apportionment between owners go to the Valuation Office Agency. Appeals against surcharges, a deemed commencement date and decisions on relief go to the Planning Inspectorate. The provisions sit at regulations 113 to 119, each with its own short deadline.
Do phased permissions need separate notices?
Yes. On a phased permission each phase is a separate chargeable development with its own commencement notice. Serving a single notice for the whole scheme and then starting a later phase months afterwards is a common and costly error. Check whether the permission is phased for CIL purposes before assuming one notice covers everything.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.