There are two types of causation which are necessary to establish criminal liability. These are factual causation and cause in law (also known as legal causation).
Factual causation means that the defendant can only be found guilty if the consequence would not have happened ‘but for’ the defendant’s conduct. This was seen in the case of Pagett (1982). Similarly, a defendant cannot be found guilty if the victim’s death was unrelated to the defendant’s actions (as in White, 1910).
Legal causation, where the actions of D must be found to have caused the consequence, can be established as long as the ‘chain of causation’ (between the act and the consequence) has not been broken.
There are a number of ways in which this chain can be broken,: Firstly, through the act of a third party, an example of which is medical treatment that is deemed to be ‘palpably wrong’ such as that seen in Jordan (1956); Secondly, where the victim’s own act is so daft as to not be reasonably expected, as seen in Williams (1992); Finally, as a result of a natural but unpredictable event, such as a flood or an earthquake.
Despite external factors, the chain of causation is not deemed to have been broken as long as the D’s actions are more than a ‘minimal’ cause of the consequence. Similarly, the defendant must also take the defendant as they find them. This is known as the ‘thin skull rule’ (as seen in Blaue 1975), meaning that there is legal causation even if D’s actions would not have caused those consequences in a regular or normal person.