The decision in Orr v Milton Keynes Council gets to the heart of a very difficult area of discrimination law, usually described as causation, but this is itself a problematic term, as the case demonstrates. The claimant suffered harassment for which his employer was vicariously liable, but was dismissed fairly for his rude and abusive response to it. It was held that the dismissal was not tainted by discrimination notwithstanding the racist provocation because a white employee would also have been dismissed for a comparable act of misconduct. The problem is not an entirely new one and a similar result was reached by the Court of Appeal in Sidhu v Aerospace Composite Technology, not mentioned in the judgment.

However, the analysis in Sidhu focused on the question of whether or not it was race discrimination to fail to take the context of the racist abuse into account as possible mitigating circumstances. It does not appear to have been suggested explicitly by anyone that the dismissal flowed from the tortious act of discrimination itself, even at the Employment Appeal Tribunal where the provocation was held to have occurred in the course of employment. Nevertheless, precisely such an outcome would result from the use of a ‘but for’ test, as indeed was unsuccessfully argued in Orr. Strict causation does not apply.

The problem is that, in practice, a ‘but for’ test is often used as a shorthand, an approach endorsed by no less an authority by Lord Goff in James v Eastleigh Borough Council, although it should be noted that he only said that it was appropriate in ‘most cases’. A more cautious note has been sounded in the subsequent decisions of the Law Lords, in a series of cases beginning with Nagarajan v London Regional Transport. In West Yorkshire Police v Khan, Lord Nicholls said, “Contrary to views sometimes stated, the third ingredient (’by reason that’) does not raise a question of causation as that expression is usually understood.” Instead, the reason why should be assessed subjectively, as a question of fact.

On the other hand, the approach in Nagarajan, which requires consideration of the state of mind of the alleged discriminator, can also be misinterpreted. It does not affect the principle in James v Eastleigh Borough Council that the motive for discrimination is irrelevant. Motive must be assessed only for the purposes of determining whether the treatment is less favourable, not whether the less favourable treatment can be justified in some way. The key lesson is that both the ‘but for’ approach and the ’state of mind’ approach can sometimes be convenient shorthands but they are not substitutes for a proper understanding and analysis of the case law. In particular, where an act is inherently race-neutral, such as a dismissal for aggressive behaviour, the Nagarajan approach is often likely to be more appropriate.