CIL forms for a London planning application cost £49 with us, and they are included free in every planning package we prepare. They are the forms a council uses to work out the community infrastructure levy on new floor space.
The levy is a charge on new development, set by the council, and it is spent on roads, schools and other local infrastructure. A typical house extension falls below the threshold and pays nothing, but the council may still ask for the forms to confirm that. Getting them right matters, because a council can refuse to validate an application that arrives without the information it needs. This article explains the threshold, the forms and the exemptions.
What the forms cost
The stand-alone fee is £49. If you commission planning drawings from us, the forms are completed as part of the package at no extra charge, because the information they ask for, the floor area of what exists and what is proposed, comes straight from the drawings.
The council's own levy, if one is due, is a separate sum paid to the council. Its rate per square metre is set in the council's charging schedule, and we do not print a figure here because each council publishes its own.
Who pays the levy
Government guidance sets the starting point. Most new development which creates net additional floor space of 100 square metres or more, or creates a new dwelling, is potentially liable for the levy. Development of less than 100 square metres does not pay, unless it consists of one or more dwellings and does not meet the self-build criteria.
| Project | Likely position |
|---|---|
| Single-storey rear extension under 100 square metres | Not liable |
| Loft conversion adding no new floor area outside the existing roof | Not liable, if under the threshold |
| Large extension of 100 square metres or more | Potentially liable |
| New house on a plot | Potentially liable, unless self-build relief applies |
| Residential annex or extension | May qualify for an exemption, under strict criteria |
The forms, and when they are needed
Applicants for planning permission are expected to submit Additional CIL Information (Form 1) alongside the application, and the guidance warns that planning authorities may refuse to validate it if the information is not provided. The form tells the council the floor area of the existing building and the new development, so it can calculate the levy.
Assumption of Liability (Form 2) is the form in which a named person accepts responsibility for paying the levy. Where someone else was named at the outset, a self-build applicant who qualifies must complete a form of their own. Check your council's rules on when each must be in.
- Form 1, Additional CIL Information: submitted with the planning application.
- Form 2, Assumption of Liability: names who pays, before development starts.
- Self-build and exemption claim forms: used where the project qualifies, and filed before work begins.
Reliefs and the cost of getting it wrong
The guidance says relief or exemption is available for residential annexes and extensions, and for houses and flats built by self-builders. It adds that there are strict criteria that must be met, and procedures that must be followed, to obtain it. If work starts before an exemption is claimed, the relief can be lost, so the order of steps matters.
The figures in this article, and where they come from
Most new development creating net additional floor space of 100 square metres or more, or a new dwelling, is potentially liable for the levy.
Source: GOV.UK, Community infrastructure levy (planning practice guidance)Development of less than 100 square metres does not pay the levy unless it consists of one or more dwellings that do not meet the self-build criteria.
Source: GOV.UK, Community infrastructure levy (planning practice guidance)Applicants should submit Additional CIL Information (Form 1) alongside their planning application, and authorities may refuse to validate it if not provided.
Source: GOV.UK, Community infrastructure levy (planning practice guidance)Assumption of Liability (Form 2) must be submitted to the collecting authority by the person who will pay the levy.
Source: GOV.UK, Community infrastructure levy (planning practice guidance)Section 206 of the Planning Act 2008 allows a charging authority to charge the levy on development in its area.
Source: legislation.gov.uk, Planning Act 2008, section 206A council has 8 weeks to decide a non-major planning application from the day after it receives it.
Source: legislation.gov.uk, Development Management Procedure Order 2015, article 34
Questions people ask
Does my extension have to pay the levy?
Probably not. Under 100 square metres of new floor space, and not a new dwelling, it is not liable. Your council's charging schedule confirms. A very large extension, or one creating a separate dwelling, is a different case.
Do all London councils charge the levy?
Councils choose whether to adopt a charging schedule. Whether and how much applies depends on the borough, so we check the council's position before the forms go in.
What if the council asks for the forms after I apply?
A council that does not have the information can refuse to validate the application. If you did not submit Form 1, send it promptly. Our packages include the forms, which avoids the delay.
Can I claim self-build relief for my own house?
If the project meets the criteria, yes, but there are strict conditions and procedures, and the claim must be made before work starts. Take advice on the route before you begin.
Is the levy the same as the planning fee?
No. The planning fee pays for the council to process the application and is set nationally. The levy is a charge on the new floor space, set locally, and is paid after permission. They are separate bills.
CIL Forms: from £49
What you get
- CIL forms completed for your application
- Floor areas taken from your drawings
- Included free with every planning package
The total you pay, fixed in writing before you commit. Council fees are separate and paid to the council. Prices checked 24 October 2026.
How our cil forms service works