The Court of Appeal (COA) has recently clarified a number of principles to which a defendant must adhere in order to meet the 'state of scientific and technical knowledge defence' in product liability proceedings.

The COA decision arose out of the DePuy Orthopaedics and related companies* hip implant litigation where DePuy is defending personal injuries claims for damages arising out of the insertion of allegedly defective hip implants.

The defendants were relying on the defence contained in Section 6(e) of the Liability for Defective Products Act 1991. This defence provides that a producer shall not be liable under the Act if he or she can show that "the state of scientific and technical knowledge at the time when he put the product into circulation was not such as to enable the existence of the defect to be discovered".

The plaintiff sought additional particulars of the DePuy defendants' defence regarding the state of scientific and technical knowledge that existed at the time the product was put into circulation. The defendants refused to provide the particulars so an application was brought before the High Court seeking an order compelling them to do so. The High Court granted the order which the defendants appealed.

In dismissing the appeal, the COA highlighted the general rule that defendants are obliged to furnish the particulars of facts on which they intend to rely in their defence. The COA went on to say that all that was being asked of the defendants was to provide the facts, those being, the state of the scientific and technical knowledge at the time the product was put into circulation. The defendants argued that such information was already contained in the expert reports which had already been submitted in the case. However, the COA held that such expert reports cannot fulfil an obligation to deliver particulars of fact in a pleading.

The COA also stated that an affidavit of verification sworn could or should not have been sworn without the defendants having identified what it considered to be the state of scientific and technical knowledge at the time of circulation relevant to the alleged defective products. Without identifying and considering this information the COA held that an arguable defence could not have been formed.

This case highlights and clarifies a number of principles to which all defendants who seek to rely on the state of scientific and technical knowledge defence under the 1991 Act must adhere. Firstly, a defendant must furnish all the facts that it intends to rely on in its defence. Secondly, expert reports cannot be used to fulfil the obligation to deliver particulars of fact in a pleading and finally, a person who swears an affidavit of verification must be able to verify all facts relied upon.