R v Warwickshire CC ex p Powergen,  EGCS 127, concerned Powergen's application to redevelop the former Avon Power Station to provide a supermarket with associated car parking and filling station, with access from Emscote Road, Warwick. After consulting the county highway authority, the district planning authority refused planning permission on the grounds of poor traffic visibility at a proposed junction. On appeal, a planning inspector granted planning permission subject to a condition requiring the widening of a canal bridge which led to the junction.
Compliance with this condition meant Powergen had to enter into a s278 agreement with the county highway authority to enable the widening to be carried out. Powergen challenged Warwickshire's refusal to sign the agreement. The court ruled that Warwickshire had no choice.