Section 106A (11) of the 1990 Act stipulates that a planning obligation may be amended or fulfilled at any time in agreement between the competent authority and the person against whom it is enforceable. The competent authority is the Mayor of London (where the planning obligation is enforceable), the Secretary of State (if it is an authorization obligation) and the local planning authority (in all other cases). The balance between the use of S106 and CIL will vary depending on the type of territory and the type of development. In the April 2014 CIL guideline, there are other indications on the balance between s106 and CIL: if the s106 is not respected, it is enforceable against the person who made the commitment and any subsequent owner. The s106 may be imposed by omission. An application to amend or discharge the s106 agreement may be submitted to the local planning authority after the expiry of the “relevant period” and the “relevant period” is defined as five years since the beginning of the date the S106 agreement was concluded. Section 106 of the Town – Country Planning Act 1990 provides that a local planning authority can enter into an agreement with anyone interested in the route on its territory to limit or regulate their development or use. A Section 106 agreement is a contract of engagement between a developer, a landowner and a local planning authority. Section 106 agreements are generally concluded as a result of a decision that, by a local planning authority, issues building permits to mitigate the impact of new developments and contains provisions to secure infrastructure on and off the site, financial contributions and other mitigation measures. With respect to developer contributions, the Community Infrastructure Tax (CIL) did not replace the Section 106 agreements, which strengthened the s 106 tests.
S106 agreements on developer contributions should focus on correcting the specific weakening required for a new development. CIL was designed to address the broader effects of development.