Tiwana Construction Limited v Secretary Of State for Housing, Communities and Local Government & Anor

An inspector determining a planning appeal must take account of an executed planning obligation which is obviously material to the planning balance, even where it is submitted after an agreed deadline and in a different form from that originally contemplated.

Where the provision of affordable housing is an important and contentious issue, the inspector must explain in the decision letter why a proffered obligation and the affordable housing it secures have not been considered. Subsequent evidence cannot ordinarily cure a failure to give reasons where the duty to give reasons is a condition of legality. A failure to consider an obviously material consideration is irrational, even if it might not have altered the outcome.

The claimant sought statutory review of an inspector’s dismissal of its appeal against refusal of outline planning permission for 10 self-build houses.

After the appeal hearing, the inspector allowed time for an executed section 106 agreement providing three affordable housing units. The claimant ultimately supplied an executed unilateral undertaking, accompanied by legal submissions proposing its acceptance with a Grampian condition. The inspector did not consider it and omitted affordable housing from the decision’s planning balance.

The issues were whether reasons were required for that omission, whether the reasons given were adequate, whether substantial prejudice resulted, whether relief should be refused, and whether the omission was an irrational failure to consider an obviously material consideration.

1. Reasons. The provision of affordable housing was an important and contentious issue. It had been a reason for refusal, and the inspector had indicated that it could be a positive factor in the planning balance. The inspector therefore had to explain in the decision letter why the unilateral undertaking and its affordable housing provision were not taken into account.
2. The decision letter, read with the relevant pre-decision exchanges, explained why an executed section 106 agreement had not been received, but did not explain the inspector’s approach to the unilateral undertaking or the alternatives proposed with it. The inspector’s later witness statement and internal exchanges could not enhance the statutory reasons required in the decision letter. The claimant suffered real and substantial prejudice because it could not properly assess the lawfulness of the decision or whether a different proposal might be acceptable.
3. Material consideration. The executed undertaking was a substantial professional document, addressed a matter raised by the inspector, and was accompanied by reasoned submissions. The difference between a section 106 agreement and a unilateral undertaking did not justify disregarding the affordable housing provision. Both mechanisms had equal legal status, and any differences went, at most, to weight. A consideration may be obviously material and require consideration even though it is not determinative.
4. The inspector’s failure to consider the undertaking and affordable housing was irrational and amounted to a failure to have regard to an obviously material consideration.
5. Relief. The reasons challenge was not a case in which relief could ordinarily be withheld after substantial prejudice had been established. Although the draft decision suggested that the outcome would probably have been unchanged, it did not establish that the outcome would necessarily have been the same. Both grounds succeeded. Subject to further submissions on the form of relief, the decision was to be quashed.

First-instance statutory review of the inspector’s decision dated 20 August 2024. The judgment records no earlier court decision.