Report of the 'Beyond the Standard Model' working group of the 1999 UK Phenomenology Workshop on Collider Physics (Durham)

The 'Beyond the Standard Model' working group discussed a variety of topics relating to exotic searches at current and future colliders, and the phenomenology of current models beyond the standard model (SM). For example, various supersymmetric (SUSY) and extra dimensions search possibilities and constraints are presented. Fine-tuning implications of SUSY searches are derived. The implications of Higgs (non)discovery are discussed, as well as the program HDECAY. The individual contributions are included separately. Much of the enclosed work is original, although some is reviewed. (author)