Judgment in the case of Barker v Corus (UK) Limited was handed down by the House of Lords on 3 May, 2006. By a majority decision, the House clarified the 'Fairchild Exception' and ruled that proportionate damages are payable in mesothelioma claims that fall within the exception. In a separate development, the Government announced on 20 June its proposals to reverse the effect of the Barker decision through an amendment to the draft Compensation Bill.

Balance of probabilities

The overriding principle in the law of tort is that a claimant must prove on the balance of probabilities that a defend-ant's conduct caused, or materially contributed to, the loss the claimant has suffered. Once this has been established, defendants are jointly and severally liable for any damages due to the claimant.

However, these principles created problems in cases where a claimant with mesothelioma was negligently exposed to asbestos by a number of employers, and medical science is such that the claimant could not establish precisely when the harmful exposure occurred.

In response to this problem, the House of Lords in Fairchild v Glen-haven Funeral Services Limited [2002] held that if a claimant could show that a defendant 'materially increased the risk' of the claimant developing the condition, then the claimant could recover in full from the defendant even if there were other tortfeasors.

In Fairchild, the House did not consider cases in which the asbestos exposures resulted from non-tortious factors. Nor did they consider proportionate liability.

Barker was one of three appeals the House of Lords was asked to consider. Mr Barker died of asbestos-related mesothelioma in 1996. During his working career he had been exposed to asbestos three times. The first two occurrences were a consequence of breaches of duty by his employer, while the latter occurred during a period of self-employment. Thus, unlike Fairchild, not all of the exposures to asbestos involved breach of an employer's duty.

The first question put to the House was whether the introduction of a nontortious contributing factor, namely exposure during a period of self-employment, takes a case outside the Fairchild Exception.

The second question concerned whether it was just and equitable for defendants to be jointly and severally liable for any damages awarded to the claimant under the Fairchild Exception.

In his lead judgment, Lord Hoffman confirmed that the Fairchild Exception can apply notwithstanding the presence of non-tortious causative factors. However, in seeking to limit the application of the Fairchild Exception, Lord Hoffman said that it is a condition of the exception that each of the causal factors contributing to the claimant's condition must have operated in the same way.

Therefore, the Fairchild Exception will only apply in circumstances where the defendant, or even the claimant, has materially increased the risk of disease through the same agent. It will not apply in cases where the claimant's condition is caused by a number of causal factors operating in a different way (such as exposure to asbestos and an additional causal factor, such as smoking) and it cannot be proved which is more likely to have been the causative agent.

As regards the issue of apportionment of damages, Lord Hoffman argued that the effect of Fairchild was to impose liability on defendants on the exceptional grounds that they may have caused harm to the claimant, not that they actually caused the harm (which is the usual basis on which damages in tort are calculated).

This, Lord Hoffman argued, meant that joint and several liability would not apply in successful claims under the Fairchild Exception. Thus, in cases involving multiple exposures to asbestos – including periods for which the claimant himself was responsible – damages will be apportioned among the defendants according to the extent to which they 'materially increased the risk' of injury to the claimant.

The Barker claim was remitted to the High Court to determine the amount payable by the culpable employer, with Lord Hoffman suggesting the most practical method will be time exposure. This may be overtaken by events depending on the wording of the amendment to the proposed Compensation Bill.

Lord Hoffman's judgments were affirmed by Lords Scott and Walker and Baroness Hale.

In dissenting, Lord Rodger argued that the decision concerning apportionment would create inconsistencies in the law and that, within what he described as the 'enclave' of the Fairchild Exception, claimants would unjustly shoulder the burden of any defendant's insolvency.

"Outside the enclave, claimants whose husbands are killed in an accident for which the only solvent defendant is, say, 5% to blame recover the whole of their damages from that defendant," he commented.

There will be uncertainty in this area of law until the position is known in relation to the Compensation Bill and how it will impact upon mesothelioma claims. Following Barker, defendants and insurers are no longer liable in respect of 'orphan' shares – where a joint tort-feasor is untraceable or insolvent.

While this is a positive development for the insurance industry and companies self-funding asbestos claims, the decision – unless and until reversed by statute – will also have an impact on case handling and possibly delay settlements while defendants conduct a detailed investigation of the claimant's employment history and the nature of the exposures to asbestos.

In many asbestos-related cases, the claimant is already deceased or unable to remember with sufficient clarity the events which took place many years ago. There is often limited documentation and/or witness evidence and, inevitably, the parties will resort to the courts to resolve factual disputes.

The decision in Barker and the restatement of the Fairchild Exception are not restricted to asbestos disease claims and may make it easier for claimants to succeed in other cases involving difficult issues of causation. These may includes claims involving product liability and clinical negligence where the claimant can show that, despite there being several causal factors, the defend-ant's conduct materially increased the risk of the damage claimed.

Fiona Gill is a partner and Alan Twine a trainee solicitor at Davies Arnold Cooper.