Controversy surrounds whether Peel Airports had any incentive to promote the airport. The original lease between the Sheffield Development Corporation and Tinsley Park Ltd included a reversionary clause permitting the buyback of of land for £1, if it could be shown that - after 10 years of opening - the airport was not financially viable. Peel's proposal to turn the airport into Sheffield Business Park was advertising land at up to £220 per square foot. The estimated profit on the site was more than £1,000,000.