This chapter explores the role of the legislature in the collaborative constitutional scheme. It argues that the central role of the legislature is to scrutinise, check, and deliberate on policy proposals put forward by the Executive. The Executive proposes, whilst the legislature deliberates and disposes. Drilling down into the detail of legislative engagement with rights in the Westminster Parliament, this chapter showcases the Joint Committee on Human Rights (JCHR) as a key site for parliamentary deliberation and scrutiny on matters of rights. In this chapter, the JCHR is presented as a hybrid constitutional watchdog, which works alongside, and in collaboration with, other constitutional and accountability actors across the Westminster landscape.