Core institutions of the state and how they interrelate

All developed states have three branches: a legislature, an executive and a judiciary. Each branch may be defined by its relationship to the law, in that:

  • the legislature makes it,
  • the executive executes it, and
  • the judiciary interprets it.


In addition, since the United Kingdom is a constitutional monarchy, the Crown is a fourth branch, albeit that its function is now mostly ceremonial.  This chapter focuses on the legislature, executive and Crown: their roles and inter-relationships.

In Britain, the legislature is its Parliament, which plays a central role in determining the executive and its policies.  The executive performs two roles:

  • political: which is concerned with policy and is performed by the government, which is headed by its cabinet.
  • administrative: which is concerned with carrying out day to day functions, which is performed mostly by the civil service.