This Practice Note explains the powers granted to Health and Safety Executive (HSE) inspectors, local authority environmental health officers and inspectors from the Office of Rail and Road (ORR) and the Office of Nuclear Regulation (ONR) to enforce health and safety law in England, Wales and Scotland. It covers the basis of the HSE’s powers and other health and safety enforcement bodies, the nature and scope of powers, including warrant cards issued to HSE inspectors, the conduct of investigations, the power to conduct interviews and the service of Prohibition Notices and Improvement Notices on dutyholders. It also covers the ability to prosecute health and safety offences in England and Wales.