Using section 73 of the Town and Country Planning Act 1990 ("the Act"), developers can vary or remove conditions attached to a planning permission.
Applications made under section 73 of the Act are commonly referred to as 'minor material amendment' applications, despite the statute making no express reference to these words. The judgment in Armstrong v Secretary of State for Levelling-Up, Housing and Communities  EWHC 176 (Admin)("Armstrong"), recently handed down by the High Court, confirms that this conception is unhelpful and fundamentally incorrect.
The outcome of the court's decision in Armstrong is that we should refrain from considering section 73 applications in terms of 'minor material amendments' and that, so long as any proposed variations do not go so far as to amend the operative part of a planning permission itself, then the application should be able to succeed, whether or not the variation is minor or otherwise.
Historically, what has been the scope of section 73 applications?
The Act provides that section 73 applies to "applications for planning permission for the development of land without complying with conditions subject to which a previous planning permission was granted" (section 73(1)).
When receiving a section 73 application, the local planning authority ("LPA") must consider only the question of the conditions subject to which planning permission should be granted and either (i) grant planning permission with varied conditions or no conditions at all or ii) refuse the application (section 73(2)).
Several cases have dealt with the application of section 73 planning permissions and have provided insight into their workings, as well as key points for developers and practitioners to consider when dealing with them.
R. v Coventry City Council Ex p. Arrowcroft Group Plc  7 WLUK 647 ("Arrowcroft") concerned a judicial review of an LPA's resolution to approve a section 73 application. The question for the court was whether the LPA had the power to grant a new planning permission, where the varied conditions would be 'fundamentally inconsistent' between the conditions and description of the development. The court found that any altered conditions would have to be ones that could have been lawfully imposed under the original planning permission and, in this case, the new conditions did not satisfy that test. This was because the new proposal of constructing six non-food retail units was fundamentally different from the original proposal related to a single-variety superstore.
In another case, R. (on the application of Vue Entertainment Ltd) v City of York Council  EWHC 588 (Admin), the judge considered the limits of section 73 applications and highlighted the fact that "section 73(2) does not limit in any way the nature of the condition, other than as to time, which can be amended under that section" [at paragraph 8]. The case involved a condition that had been varied, so that a sports stadium development could include a 13-screen, 2,400-person cinema complex, rather than one with 12 screens seating 2,000 people. It was held that a change to the condition in this case did not fundamentally alter the permission itself, which did not mention or define the size of cinema.
In John Leslie Finney v Welsh Ministers, Carmarthenshire County Council, Energiekontor (UK) Limited  EWCA Civ 1868 ("Finney"), a section 73 application was made to vary one of the conditions of a previous planning permission relating to the tip length of two wind turbines. The description of the previous planning permission and its associated condition referred to a "tip length of 100m", whereas the variation provided for 125m. Although the inspector dealing with the application allowed the variation, the decision was held to be unlawful. This was because section 73(1) limits a LPA's considerations to the question of conditions only. Here, by allowing the variation of the condition, it would have the effect of also altering the description of the previous planning permission (specifying a tip height of 100m) and this was not permissible. The case is authority for the fact that section 73 applications cannot be used where their grant would lead to a variation to the description of a previous planning permission.