Learning Outcomes
This article explains the concept of factual causation as a key element in establishing negligence. It focuses specifically on the 'but for' test, its application, and its limitations. For the SQE1 assessment, you need to understand how to apply the 'but for' test to determine if the defendant's breach of duty factually caused the claimant's harm. Your understanding will allow you to analyse scenarios and identify the correct legal outcome regarding factual causation in multiple-choice questions.
SQE1 Syllabus
For SQE1, establishing causation is fundamental to a successful negligence claim. You will need to demonstrate an understanding of the principles of factual causation, particularly the application of the 'but for' test. As you revise this topic, focus on:
- The definition and role of factual causation within the elements of negligence.
- The 'but for' test as the primary method for establishing factual causation.
- Applying the 'but for' test to given factual scenarios.
- Recognising situations where the 'but for' test may present difficulties, such as cases involving multiple potential causes.
- Understanding the standard of proof required (balance of probabilities).
Test Your Knowledge
Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.
-
What is the primary test used to determine factual causation in negligence?
- The reasonable foreseeability test
- The material contribution test
- The 'but for' test
- The proximity test
-
In the context of factual causation, what standard of proof must the claimant meet?
- Beyond reasonable doubt
- Clear and convincing evidence
- Balance of probabilities
- Prima facie evidence
-
Which case famously illustrates the application of the 'but for' test where a doctor's negligence did not factually cause the patient's death?
- Donoghue v Stevenson
- Caparo Industries plc v Dickman
- Barnett v Chelsea & Kensington Hospital Management Committee
- Bolam v Friern Hospital Management Committee
Introduction
Once you have established that a defendant owed the claimant a duty of care and breached that duty by falling below the required standard of care, the next essential element in a negligence claim is causation. The claimant must prove that the defendant's breach of duty actually caused the damage suffered. Causation is divided into two main parts: factual causation and legal causation. This article focuses on factual causation, specifically exploring the primary test used by the courts: the 'but for' test. Understanding factual causation is essential for determining liability in negligence.
Factual Causation: The 'But For' Test
The fundamental principle of factual causation is to establish a link between the defendant’s breach of duty and the claimant’s harm. The main test the courts apply is the 'but for' test.
Key Term: Factual Causation The principle that the defendant's breach of duty was, as a matter of fact, a cause of the claimant's damage. It addresses the question: did the defendant's actions actually lead to the claimant's harm?
Key Term: 'But For' Test The primary test for factual causation which asks: 'But for the defendant's breach of duty, would the claimant have suffered the harm?'
If the answer to the 'but for' question is 'no' (i.e., the harm would not have occurred without the defendant's breach), then factual causation is established. If the answer is 'yes' (i.e., the harm would have occurred anyway, regardless of the defendant's breach), then factual causation is not established, and the negligence claim will fail at this stage.
The burden of proving factual causation rests on the claimant. The standard of proof is the balance of probabilities, meaning the claimant must show it is more likely than not (over 50% probability) that the defendant's breach caused the harm.
Applying the 'But For' Test
The application of the 'but for' test is often straightforward in cases with a single, clear cause of harm. The classic illustration is Barnett v Chelsea & Kensington Hospital Management Committee [1969] 1 QB 428.
Worked Example 1.1
A patient attended a hospital casualty department complaining of severe stomach pains and vomiting after drinking tea. The doctor on duty negligently failed to examine the patient and sent him home, telling him to contact his GP. The patient later died from arsenic poisoning contained in the tea. Medical evidence showed that even if the doctor had examined and treated the patient correctly, the patient would have died anyway due to the severity of the poisoning. Did the doctor's negligence factually cause the patient's death?
Answer: No. Applying the 'but for' test: but for the doctor's negligent failure to examine the patient, would the patient still have died? Yes, the evidence indicated death was inevitable due to the poisoning. Therefore, the doctor's breach was not the factual cause of death.
Limitations of the 'But For' Test
While the 'but for' test is the starting point, it can be difficult to apply, particularly in situations involving multiple potential causes of harm.
Worked Example 1.2
A factory worker develops lung disease after many years of exposure to dust. Some dust exposure ('innocent dust') is an unavoidable part of the job, even with precautions. However, due to the employer's negligence in maintaining extraction equipment, the worker was also exposed to excessive amounts of 'guilty dust'. It is impossible to say definitively whether the disease was caused by the 'innocent' dust, the 'guilty' dust, or the cumulative effect of both. How might the 'but for' test apply here?
Answer: Applying the 'but for' test strictly is problematic. Can the worker prove that 'but for' the negligent exposure to 'guilty dust', they would not have developed the disease? It might be difficult if the 'innocent' dust exposure alone could have caused the illness. This highlights a limitation of the 'but for' test in multiple cause scenarios. (Note: In such cases, courts may consider alternative tests like 'material contribution to harm', which are beyond the scope of this specific article focusing on the 'but for' test).
Exam Warning
For SQE1, ensure you can apply the basic 'but for' test correctly. Be aware that questions might present scenarios where causation seems likely but fails the 'but for' test (like Barnett), or where its application is complicated by multiple factors. Focus on whether the claimant can prove, on the balance of probabilities, that the harm would not have occurred but for the specific breach identified.
Key Point Checklist
This article has covered the following key knowledge points:
- Factual causation is the first stage in establishing the causal link between the defendant's breach and the claimant's harm in negligence.
- The primary test for factual causation is the 'but for' test.
- The 'but for' test asks: 'But for the defendant's breach of duty, would the claimant have suffered the harm?'
- If the harm would have occurred regardless of the breach, factual causation is not established.
- The claimant must prove factual causation on the balance of probabilities.
- The Barnett v Chelsea & Kensington Hospital case is a key example of applying the 'but for' test.
- The 'but for' test can be difficult to apply in situations involving multiple potential causes.
Key Terms and Concepts
- Factual Causation
- 'But For' Test
