An alternative to the Wayne Tank rule in the FCA test case

It has been over one year since the Supreme Court's judgment in Financial Conduct Authority v Arch Insurance (UK) Ltd [2021] Lloyd's Rep IR 63 (the "FCA test case"). Among the many aspects that were decided by the Supreme Court, the "proximate in efficiency" test of causation was reified and systematised. This article will attempt to find grounds for replacing the Wayne Tank principle with a new test for concurrent causation.

One of the main questions before the Supreme Court in the FCA test case was the cause of the business interruption losses. The court found that each case of Covid-19 in England was a concurrent cause of the losses, ¹ as opposed to the underlying disease itself. In answering issues on causation flowing from this finding, the court restated and redefined some aspects of the test of the proximate in efficiency cause. ²