Our Principles, Policies and Procedures Learn about the MU's principles and ethos as an organisation and how you can give us feedback. Last updated: 25 September 2023 At the Musicians' Union we are committed to acting ethically and treating all members equally. As a Trade Union, our Rules are an important resource for members and provide a framework for our activities and democratic structure. Find out what you can expect from us as an MU member by getting familiar with our Service Level Committment.