The primary difference between common law and statute law in the UK lies in their origin and development. Common law is judge-made law, derived from case decisions and historical customs, while statute law is created by Parliament through legislation. Common law sets legal precedents based on judicial decisions, which can be used as guidance in future cases, whereas statute law is applied uniformly to all relevant cases. Additionally, statute law can override or amend common law provisions, while common law cannot change statute law.