Systematic review of contracting acute hospital care

systematic review of published academic literature and government policy documents about contracting of health services in UK in the last ten years. Health services that I am interested in is acute hospital services. I want to understand how it changed over the last ten years, how it is done now and what are the expectations (according to policy documents and academic literature) for coming years. Some information about empirical research and methodology applied in past research would be desirable. I would also need full reference to all sources consulted.