This document provides information about offences of grievous bodily harm (GBH) and GBH with intent under sections 20 and 18 of the Offences Against the Person Act 1861. It defines the actus reus and mens rea requirements for each offence, and explains that section 18 requires a specific intent to cause GBH or resist arrest, while section 20 only requires recklessness as to harm. Several cases are discussed that illustrate the level of injury required for GBH and how intent versus recklessness is assessed. Scenarios are presented to demonstrate how to determine the appropriate offence based on the injury caused and the defendant's state of mind.