Issues such as change in legislation continue to influence variations in project costs and time. Health and safety legislation has been particularly influential on the projects studied. Projects need to allow for legislative and regulatory change, based on issues such as environmental remediation and any harmonisation within Europe. The private sector will not accept this risk (outside of regulatory risk normal in a business environment) except at a high price premium, so allowances should continue to be made in business cases. It is important to ensure that research is carried out in this area during the project life-cycle in order to anticipate potential changes and put in place mitigation strategies.