The report describes some of the technical risks and opportunities in the application of blockchain technologies within government and industry, and how to assess whether blockchain-based systems will meet critical requirements. The project explores this primarily through the description and analysis of high-level design alternatives for illustrative ‘use cases’. Three use cases have been selected after a number of initial workshops and preliminary research: remittance payments, open data registries, and agricultural supply chain. These provide reasonable coverage of various kinds of requirements and regulatory concerns, against which we can evaluate design alternatives, and in turn learn more general lessons about blockchain technologies. In addition to this design-based analysis, we also report on some empirical results from testing prototype implementations.