Cooper & Anor v Thameside Construction Company Ltd

In a civil claim based on competing explanations, the claimant retains the burden of proving its case on the balance of probabilities. The court may analyse and eliminate competing theories, but elimination alone does not establish the remaining theory. The court must stand back and decide whether the preferred explanation is more likely than not, applying common sense and recognising that the evidence may remain too uncertain for a positive finding.

Where the evidential picture contains significant gaps and credible alternative explanations remain, the claimant may fail even though the defendant cannot identify the true cause. Adverse inferences from an absent witness require a sufficient evidential foundation and may be weakened or nullified by a credible explanation for the absence.

The claim arose from a substantial flood at the claimants’ residential property. The claimants alleged that a defective Polyplumb connector had been installed by Thameside Construction Company Ltd or its plumbing sub-contractor, Darenth, during works carried out under a JCT contract.

Thameside accepted that the connector was defective and that the defect caused the flood. Its remaining defence was that neither it nor anyone for whom it was responsible had installed the connector. The central issue was therefore whether the installation had been carried out by Thameside, Darenth, or another contractor working independently of Thameside.

The judgment concerned liability following an earlier order for a split trial.

1. Burden of proof. The claimants bore the burden throughout of proving, on the balance of probabilities, that Thameside or a person for whom it was responsible installed the failed connector. Thameside did not have to prove an alternative cause or identify the actual installer.
2. Competing theories. The court applied the approach in Rhesa Shipping Co v Edmunds (the Popi M) and the later authorities. It was permissible to analyse competing explanations systematically and to eliminate less plausible possibilities. That exercise did not itself establish the remaining explanation. The court had to stand back and decide whether the preferred explanation was more likely than not, having regard to the whole evidential picture, including evidential gaps and alternative explanations.
3. Factual findings. The connector was defectively installed, probably through use of a previously deformed grab ring. The court found that Mr Johnson carried out the first and second fix plumbing for the basin, but did not install the Polyplumb connector. There were at least two realistic possibilities that another contractor, particularly Ludek or Signature, had installed it after damaging or moving the pipework. The mystery therefore remained unresolved.
4. Adverse inference. The court considered the principles in Wisniewski v Central Manchester Health Authority. It declined to infer that absent witnesses from Signature and Ludek would have given evidence adverse to the claimants. The failure to call them nevertheless weakened the claim when the evidence was assessed overall.
5. Disposition. The claimants failed to prove that Thameside or its servants or agents installed the connector. The claim was dismissed. The parties were invited to draw up an order dealing with consequential matters, including costs.

This was a first-instance liability judgment in a split trial. On 6 March 2015, Edwards-Stuart J directed that liability and quantum should be tried separately. This judgment determined liability.