PastPaperHero | Product liability - Defences under the Act

Learning Outcomes

This article outlines the statutory defences available under the Consumer Protection Act 1987 (CPA 1987). The focus is on how defendants avoid liability in strict product cases by proving one or more of the specific section 4 defences. You should be able to distinguish each defence, identify the elements that must be proved, and appreciate their limits in light of leading authority. Particular attention is given to the compliance-with-law defence, the “did not supply” and “not in course of business” defences, the timing defence where the defect did not exist when supplied, the development risks defence, and the component manufacturer defence. You should also understand how contributory negligence can reduce recovery, the prohibition on exclusion of CPA liability, the damage boundaries under the Act (including the £275 property threshold and exclusion of damage to the defective product itself), the burden of proof on defendants, and the key limitation rules (three years from damage and a ten-year long-stop).

SQE1 Syllabus

For SQE1, you are required to understand the operation of the Consumer Protection Act 1987, including the defences available to defendants. Your knowledge should allow you to identify and apply the relevant defences in specific factual scenarios presented in assessment questions, with a focus on the following syllabus points:

the specific statutory defences provided in section 4 of the CPA 1987
the 'development risks' or 'state of the art' defence and its interpretation
the defence relating to defects in component parts versus finished products
the availability of contributory negligence as a partial defence
the general inability to exclude liability under the CPA 1987
the scope of “damage” under s 5 CPA 1987 (including the £275 property threshold and exclusion of business property and damage to the defective product itself)
the burden of proof resting on the defendant in raising s 4 defences
limitation for CPA claims: three years from damage (or knowledge) and a ten-year long-stop from first circulation of the product.

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.

Which of the following defences requires the defendant to prove that the state of scientific and technical knowledge at the time of supply was such that a producer could not be expected to have discovered the defect?
1. Compliance with statutory requirements
2. Defect did not exist at time of supply
3. Development risks defence
4. Component manufacturer defence
A manufacturer supplies tyres to a car company according to the car company's design specifications. The tyres are not defective in themselves, but the design causes them to fail when fitted to the car. Can the tyre manufacturer rely on a defence under the CPA 1987 if a driver is injured?
1. Yes, the development risks defence.
2. Yes, the component manufacturer defence relating to design compliance.
3. No, liability is strict.
4. No, unless they can prove the car company was negligent.
Can a business exclude liability for death or personal injury caused by a defective product under the CPA 1987 through a contractual term?
1. Yes, if the term is reasonable.
2. Yes, if the term is fair.
3. Yes, if the consumer explicitly agrees.
4. No, liability cannot be excluded or limited.

Introduction

The Consumer Protection Act 1987 (CPA 1987) imposes strict liability on producers and others in the supply chain for damage caused by defective products. This means a claimant does not need to prove negligence. However, liability is not absolute. The Act provides specific defences in section 4 that permit a defendant to avoid liability where defined criteria are met, and it sets the boundaries of recoverable damage and applicable limitation. Understanding those defences and their limits is essential for competent application of the CPA 1987.

STATUTORY DEFENCES UNDER THE CPA 1987

Section 4(1) of the CPA 1987 provides six specific defences. The burden of proving any of these defences lies with the defendant. They are interpreted narrowly and must be established by cogent evidence.

Compliance with Legal Requirements (s 4(1)(a))

A defendant has a defence if they can show the defect was attributable to compliance with any requirement imposed by or under any enactment or with any retained EU obligation. This defence covers situations where the product’s alleged lack of safety is the direct and inevitable result of mandatory legal requirements (for example, mandatory packaging or closure features required by legislation for dangerous substances).

It is construed strictly:

the requirement must genuinely compel the characteristic giving rise to the alleged defect
conformity with general standards or industry guidance is not enough
if the law allowed manufacturer discretion, and the unsafe choice resulted from that discretion, the defence will not be available.

Defendants typically prove this defence with regulatory texts, technical conformity evidence, and design documentation showing the feature complained of was mandated and unavoidable.

Defendant Did Not Supply the Product (s 4(1)(b))

This defence is available if the defendant proves they did not supply the product to another person. It most commonly applies where products have been stolen or otherwise come into circulation without the defendant’s supply. “Supply” under the Act is broad (including sale, hire, loan, or giving away), so this defence focuses on break-in-the-chain events that bypass the defendant entirely.

Examples include:

theft of products prior to any supply
unauthorised removal from premises followed by injury to the unauthorised user
products obtained by fraud where the alleged defendant never actually supplied.

Evidence often includes batch release records, dispatch logs, and security incident reports.

Supply Not in Course of Business (s 4(1)(c))

Liability under the CPA is primarily directed at those supplying products in the course of business. Section 4(1)(c) provides a defence where the supply was not in the course of business and not with a view to profit. This covers purely private, non-business supplies (such as a person gifting a homemade item in a non-commercial context).

Points to note:

free promotional samples by traders are ordinarily “in the course of business” even if no price is charged, so the defence will not apply
repeated online sales, even of home-crafted goods, can amount to business activity depending on regularity and intention to profit
supply among friends/family on a wholly private basis will generally fall within s 4(1)(c).

Defect Did Not Exist at Time of Supply (s 4(1)(d))

The defendant can escape liability if they prove the defect did not exist in the product when it was supplied by them (or by a person liable under s 2(2), such as the producer or importer). This defence is frequently raised where the alleged fault arose post-supply through misuse, improper maintenance, modification, or wear and tear.

Evidence typically includes:

manufacturing and inspection records
product traceability and batch data
expert analysis showing post-supply change (for example, consumer modification or environmental damage).

Illustrative authority includes Piper v JRI (Manufacturing) Ltd (2006), where the manufacturer showed the fracture of a medical implant occurred long after supply and that the thorough manufacturing process made it implausible that the defect existed at supply.

Development Risks Defence (s 4(1)(e))

Often called the “state of the art” defence, this is available if the defendant proves that the state of scientific and technical knowledge at the relevant time (when the product was supplied) was not such that a producer of products of the same description might be expected to have discovered the defect while the product was under their control.

Key Term: Development Risks Defence
A defence under s 4(1)(e) CPA 1987 where the defendant proves that the state of scientific and technical knowledge at the time the product was supplied was not sufficiently advanced to allow the defect to be discovered.

Key features:

the test is objective and global: consider the highest level of accessible knowledge worldwide, not just the defendant’s internal knowledge or local practice
the focus is on discoverability, not foreseeability
if a risk is known (even if screening is difficult or costly), the defence is unlikely to succeed.

The leading case, A v National Blood Authority [2001] 3 All ER 289, confirms that known risks are incompatible with this defence. There, the risk of Hepatitis C contamination in blood was known, even though effective screening was not yet implemented. The products did not meet the safety persons generally were entitled to expect; the development risks defence failed.

The defence is more apt for “unknown unknowns” — risks genuinely undiscoverable by the then current scientific and technical knowledge. It is not a licence to rely on industry custom or cost-based limitations.

Worked Example 1.1

Pharma Co develops a new drug. Five years after its launch, scientific research reveals a previously unknown side effect causing serious harm, which could not have been detected with the scientific knowledge available at the time the drug was supplied. Can Pharma Co rely on a defence under the CPA 1987?

Answer:
Pharma Co may be able to rely on the development risks defence under s 4(1)(e). They would need to prove that, at the time of supply, the state of scientific and technical knowledge did not permit discovery of the risk.

Component Manufacturer Defence (s 4(1)(f))

This defence applies specifically to producers of component parts incorporated into a finished product. The component producer is not liable if they prove the defect in the finished product arose wholly from the design of the finished product or from compliance with instructions given by the finished product manufacturer.

Key Term: Component Manufacturer Defence
A defence under s 4(1)(f) CPA 1987 available to the producer of a component part where a defect in the finished product is attributable solely to the design of the finished product or compliance with the finished product manufacturer's instructions.

Important boundaries:

“wholly attributable” is strict: if the component itself is defective, the defence fails
where the component producer followed detailed instructions, and the defect lies in those instructions or the overall product design, the defence can succeed
independent design contributions or departures from instructions by the component producer may undermine the defence.

Worked Example 1.2

Engine Co manufactures engine components to specifications provided by Car Co. An engine fails due to a design flaw in Car Co's specification, not due to any fault in Engine Co's manufacturing process. A driver is injured. Can Engine Co rely on a defence under the CPA 1987?

Answer:
Engine Co may be able to rely on the component manufacturer defence under s 4(1)(f). They must demonstrate the defect was entirely attributable to Car Co’s design or instructions, with no defect in their component.

Worked Example 1.3

A chemical company supplies child-resistant closures for domestic bleach. Regulations mandate a specified resistance level and closure design for hazardous substances. A user suffers minor hand injuries opening the closure and argues the closure is “defective”. Can the supplier rely on s 4(1)(a)?

Answer:
If the injuries complained of are attributable to a closure design compelled by legal requirements, s 4(1)(a) may apply. The supplier would need to prove the specific closure feature alleged to be unsafe was mandated and could not reasonably be avoided while complying with the regulation.

Worked Example 1.4

A laptop is stolen from a warehouse before any supply, and later injures the thief due to an internal battery fault. The warehouse occupier is sued under the CPA. Can they rely on s 4(1)(b)?

Answer:
Yes, if they can prove they did not supply the product to another person. Unauthorised theft leading to circulation can support the s 4(1)(b) defence.

Worked Example 1.5

Alex gifts a homemade jam to a neighbour at a private party. The neighbour suffers illness and sues under the CPA. Can Alex rely on s 4(1)(c)?

Answer:
Likely yes. A purely private gift not in the course of business and not with a view to profit is covered by s 4(1)(c). Regular or commercial gifts would not be.

Worked Example 1.6

A consumer modifies a space heater by bypassing a thermal cut-out, contrary to warnings, and suffers burns. The manufacturer is sued under the CPA. Can s 4(1)(d) apply?

Answer:
Potentially. If the manufacturer can prove the defect (dangerous condition) did not exist when supplied and resulted from post-supply modification or misuse, s 4(1)(d) can defeat liability.

OTHER DEFENCES AND EXCLUSIONS

Beyond the specific defences in section 4, other legal principles can affect liability under the CPA 1987.

Contributory Negligence

The Law Reform (Contributory Negligence) Act 1945 applies to claims under the CPA 1987. If the claimant’s damage was caused partly by a defect in a product and partly by the claimant’s own fault, damages may be reduced to the extent the court considers just and equitable.

Examples:

ignoring clear warnings (for example, microwaving a “do not microwave” sealed container)
failing to use obvious safety accessories supplied with the product
continuing to use a product after observing abnormal behaviour.

The reduction mirrors principles used in negligence cases (for example, Froom v Butcher guidance on seatbelt reductions by analogy to product safety contexts where appropriate).

Key Term: Contributory Negligence (CPA 1987)
A partial defence where the claimant's damages under the CPA 1987 may be reduced if their own carelessness contributed to the damage suffered.

Exclusion of Liability

Section 7 of the CPA 1987 prevents defendants from excluding or limiting their liability under the Act through any contract term, notice, or other provision. Any attempt to do so is void. This operates alongside consumer protection statutes in the contract sphere (such as the Consumer Rights Act 2015 and, for non-consumer contracts, the Unfair Contract Terms Act 1977) but CPA liability is non-excludable regardless of the fairness or reasonableness of any term.

Boundaries of Damage under the CPA 1987

Understanding the damage boundaries is important when considering defences and overall exposure:

personal injury (including disease or impairment of physical or mental condition) is fully recoverable
damage to property is recoverable only if it exceeds £275 (s 5(4)) and is to property ordinarily intended for private use, occupation or consumption
damage to business property is excluded (s 5(2))
the cost of repairing or replacing the defective product itself is not recoverable under the CPA (it is pure economic loss).

Case illustrations:

Abouzaid v Mothercare [2001] EWCA Civ 348: even where negligence foreseeability was not established, the product could be defective under the CPA because it failed to meet safety expectations; damage analysis then follows s 5
Pollard v Tesco Stores [2006] EWCA Civ 393: “child-resistant” lid met consumer expectation even though not to the British Standard, so no defect; if there is no defect, damage analysis under s 5 is unnecessary.

Limitation

Two key limitation rules apply to CPA claims:

three-year primary limitation: actions must be brought within three years from the date of damage, or the date the claimant had knowledge of the damage and that the defect caused it (Limitation Act 1980, s 11A)
ten-year long-stop: no action may be brought after ten years from the date on which the product was first put into circulation by the relevant defendant.

The long-stop runs irrespective of the claimant’s knowledge, and separate rules protect claimants lacking capacity or minors as they would in general limitation law.

Supplier Identification Mechanism

Although not a “defence” in s 4, suppliers can avoid liability by identifying the producer, own-brander or importer. Under s 2(3) CPA 1987, a supplier will be treated as liable if, upon request and within a reasonable time, they fail to identify the person who is or could be liable under s 2(2). Prompt and accurate identification is therefore a practical route for suppliers to avoid strict liability under the CPA.

Exam Warning

While claimants do not need to prove fault, defendants can avoid liability entirely if they successfully establish one of the statutory defences under section 4. Do not elide the development risks defence with cases involving known but unavoidable risks. If a risk is known, the defence will generally fail (as confirmed in A v National Blood Authority). Remember also that contributory negligence can reduce damages even where strict liability applies.

Revision Tip

Focus on the precise elements of each s 4 defence:

for compliance with law, prove compulsion by the relevant legislation and that the defect is attributable to that compulsion
for “did not supply”, trace circulation and show absence of any supply by the defendant
for “not in course of business”, distinguish genuine private supply from business-related promotional or systematic sales
for “defect not present at supply”, gather robust manufacturing and inspection evidence
for development risks, assess global scientific and technical knowledge at the time of supply
for component manufacturer, show the defect is wholly attributable to the finished product design or instructions, with no defect in the component itself.

Understand the damage boundaries in s 5, and the three-year limitation and ten-year long‑stop. The burden of proving defences rests entirely with defendants.

Key Point Checklist

This article has covered the following key knowledge points:

The CPA 1987 provides specific statutory defences in section 4(1) which can absolve a defendant from strict liability.
The burden of proving any statutory defence rests on the defendant.
Key defences include compliance with legal requirements, non-supply, defect non-existence at time of supply, development risks, and the component manufacturer defence.
The development risks defence (s 4(1)(e)) relates to the discoverability of the defect based on scientific/technical knowledge at the time of supply and is narrowly interpreted; known risks will usually defeat the defence.
The component manufacturer defence (s 4(1)(f)) applies if the defect is due wholly to the finished product’s design or manufacturer’s instructions.
Contributory negligence operates as a partial defence, potentially reducing damages.
Liability under the CPA 1987 cannot be excluded or limited by contract terms or notices (s 7).
Recoverable damage under the CPA excludes damage to the defective product itself, excludes business property, and requires private property damage to exceed £275.
CPA limitation combines a three-year primary period and a ten-year long-stop from first circulation by the defendant.
Suppliers can avoid liability by promptly identifying the producer/own-brander/importer when requested (s 2(3)).

Key Terms and Concepts

Development Risks Defence
Component Manufacturer Defence
Contributory Negligence (CPA 1987)

Product liability - Defences under the Act