1. The two elements
Most serious offences need a guilty act or result (actus reus) and a guilty state of mind (mens rea), such as intention or recklessness, with no defence that applies.
2. They must coincide
The mens rea has to exist at the time of the act. Courts get round strict timing by treating a continuing act as one event: in Fagan v Metropolitan Police Commissioner [1969], a driver who accidentally parked on an officer's foot and then refused to move had both elements while the car stayed there.
3. When an omission counts
There's no general duty to help a stranger in English law, but a failure to act is enough where the law imposes a duty, including:
- A contractual duty: R v Pittwood (1902), a level-crossing keeper who left the gate open.
- A special relationship: R v Gibbins and Proctor (1918), parents who failed to feed their child.
- Creating a dangerous situation: R v Miller [1983], a man who started a fire by accident and did nothing to stop it spreading.