Two recent cases have provided clarification as to the scope of Section 73 for the Town and Country Planning Act 1990. This is the provision that allows applications to be made for permission to develop without complying with a condition previously imposed on a planning permission, which is often used to vary existing planning permissions by way of the substitution of new plans.
In Re (Atwill) v New Forest National Park Authority  EWHC 625, the High Court determined that the local planning authority had acted unlawfully in granting a Section 73 application where the development works had not been lawfully commenced. Therefore, the original planning permission had lapsed.
The planning permission in question was for the demolition and replacement of a dwelling. The dwelling constructed differed in terms of its positioning, footprint and dimensions from the approved plans. The developer applied to substitute the approved plans retrospectively by way of Section 73 of the Act which was granted by the local authority.
In quashing the Section 73 permission, the court said that, when determining if development has commenced, the operations relied on must be ones which can properly be said to be undertaken pursuant to the grant of the planning permission in question.
No coherent reason had been given for why the determination of the commencement of development for the purposes of Section 73 should be any different from other situations arising under the town and country planning legislation.
As development was not lawfully commenced under the existing permission, and the time period for implementation had expired, the permission was no longer extant and therefore could not be amended pursuant to Section 73 of the Act.
The High Court also held that Section 73 could not be used where the result was to change the “operative part” or the “grant” of permission – the description of the development contained in the permission.
The Section 73 permission introduced additional wording to the description of development that was not included in the original permission and which the court did not consider to be de minimis or otherwise immaterial.
In coming to that conclusion, the court referred to the recent decision in Re Armstrong v Secretary of State for Levelling-Up, Housing and Communities & Anor  EWHC 142. It was held in that case that Section 73 may only be utilised where the proposed disapplication or variation of an existing condition would not be inconsistent with the operative part of the planning permission.
In the Armstrong case, planning permission had been granted for the “construction of one dwelling”. The court held that Section 73 could be used to substitute new plans which completely redesigned the dwelling on the basis that it would cause no conflict with the operative part of the planning permission.
The court in Armstrong also concluded that there was no justification for inferring any further limitation on the scope of Section 73. Accordingly, Section 73 is available even if granting the application would bring about more than a “minor material amendment” as described in the commentary on Sections 73 in the government’s Planning Policy Guidance. They contrasted this with s96A of the Act which is expressly constrained in its scope to “non-material changes”.
These cases make it clear that Section 73 applications will be limited to variations to unexpired planning permission that do not conflict with the description of development, but that they are not limited to minor material amendments to planning permissions.