WHAT IS KNOWN ON THE SUBJECT?: Seclusion and restraint still regularly occur within inpatient mental health services. The Council of Europe requires the development of a policy on for instance age limits, techniques and time limits. However, they only define the outer limits of such a policy by indicating when rights are violated. Within these limits, many choices remain open. Staff and service managers lack clarity on safe and humane procedures. Research literature provides limited and contradictory insights on these matters. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: The study resulted in 77 best practice recommendations on the practical application of restraint and seclusion as last resort intervention in inpatient youth and adult mental health services, including forensic facilities. To our knowledge, this is the first study in which the development of recommendations on this topic is not only based on scientific evidence, but also on an analysis of European human rights standards and consensus within and between expert-professionals and experts-by-experience. This approach allowed to develop for the first time recommendations on time limits, asking for second opinion, and registration of seclusion and restraint. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: The 77 recommendations encourage staff to focus on teamwork, safety measures, humane treatment, age and time limits, asking for second opinion, observation, evaluation and registration when applying seclusion and restraint as last resort intervention. The implementation of the best practice recommendations is feasible provided that they are combined with a broad preventive approach and with collaboration between service managers, staff (educators) and experts-by-experience. Under these conditions, the recommendations will improve safety and humane treatment, and reduce harm to both service users and staff., Abstract: INTRODUCTION: Seclusion and restraint still regularly occur within inpatient mental health services. Professionals lack clarity on safe and humane procedures. Nevertheless, a detailed policy on for instance age limits, techniques and time limits is required., Aim: We developed recommendations on the humane and safe application of seclusion, physical intervention and mechanical restraint in inpatient youth and adult mental health services, including forensic facilities., Method: After developing a questionnaire based on a rapid scientific literature review and an analysis of human rights sources stemming from the Council of Europe, 60 expert-professionals and 18 experts-by-experience were consulted in Flanders (Belgium) through a Delphi-study., Results: After two rounds, all but one statement reached the consensus-level of 65% in both panels. The study resulted in 77 recommendations on teamwork, communication, materials and techniques, maximum duration, observation, evaluation, registration, second opinion and age limits., Discussion: Combining an evidence, human rights and consensus-based approach allowed for the first time to develop recommendations on time limits, asking for second opinion and registration., Implications for Practice: When combined with a preventive approach and collaboration between service managers, staff (educators) and experts-by-experience, the recommendations will improve safety and humane treatment, and reduce harm to service users and staff., (© 2022 John Wiley & Sons Ltd.)