The CIL is a charge that local planning authorities may apply to new development to help fund supporting infrastructure such as transport, schools and healthcare. Introduced under the Planning Act 2008, CIL has been in force since April 2010.

CIL is only payable in areas where the local authority has adopted a charging schedule and may apply to developments creating 100 square metres or more of new internal floorspace, or to developments that create new dwellings regardless of size.

Certain developments may be exempt or eligible for relief, including some self-build or charitable schemes. However, strict procedures apply, and failure to submit the correct forms - particularly a Commencement Notice before work starts - can result in relief being withdrawn, with the full levy and potential penalties becoming payable.

Although linked to the planning process, CIL is administered separately, and responsibility rests with the developer to establish liability and comply with all procedural and payment requirements.