Section 73 Planning Applications in London: Varying Conditions on Existing Permissions

A Section 73 application is submitted to the same local planning authority that granted the original permission. It must identify: the original planning permission reference number, the specific condition(s) you want to vary or remove, and the proposed wording of the amended condition (or a statement that you want the condition removed). Supporting information: The application should explain why the variation is sought and (for material variations) include any updated plans, drawings, or specifications that support the case. For example, if you want to vary an approved materials condition to use a different external brick, you would submit a sample or specification of the proposed brick and make the case that it is appropriate in terms of character, quality, and appearance. Pre-application discussion: Before submitting a Section 73, it is worth checking with the local planning authority whether the proposed variation is in principle acceptable. A pre-application discussion or a call to the duty planner can give an informal view on whether the Section 73 is likely to succeed — avoiding the cost and time of a refused application. The outcome of a Section 73: If the application is granted, the local planning authority issues a new planning permission, bearing a new reference number. This new permission incorporates all the conditions of the original permission, except that the varied condition is replaced with the new wording (or removed). All other conditions of the original permission are carried over. Choosing which permission to implement: Once a Section 73 is granted, both permissions exist simultaneously. The developer can choose to implement either. If the development has already started under the original permission, the Section 73 permission can still be implemented provided the works carried out so far are consistent with the new permission.

Section 73 cannot be used to change the description of development. The description of development on a planning permission is the text that describes what the permission authorises — for example, "erection of a single-storey rear extension." A Section 73 permission must have the same description of development as the original. This was confirmed by the Court of Appeal in Finney v Welsh Ministers [2019] and has been subject to ongoing case law and legislative debate. The practical implication: if you want to make a change to the development that would require a different description (for example, adding a floor to a single-storey extension to create a double-storey), you cannot do this via Section 73 — you need a new full planning application. Section 73 also cannot: be used to extend the time limit for implementing the permission — for an expired permission, a new application is required; retrospectively authorise development that has already been carried out (Section 73A is the relevant route for retrospective consent, in the rare circumstances where it applies); be used to remove a condition that is "fundamental" to the grant of permission, in the sense that without it the authority would not have granted the permission at all — such conditions must be varied or removed by applying for a fresh planning permission.