Motor insurers – running an illegality defence in the recent decision of Dormer v Wilson and others [2025]

Overview

The recent High Court liability only judgment in the case of Dormer v Wilson and MIB [2025] EWHC523 addressed a number of motor related issues in a high value personal injury claim which included:-

• The application of the illegality defence (previously referred to as the ex turpi causa rule) in tort which would, if proven, operate as a complete defence to the claimant’s personal injury claim.
• Liability under the Road Traffic Act 1988 of the insurer of a stolen motorbike.
• Causing or permitting a vehicle to be used without insurance (Section 143 of the RTA 1988).

Summary of facts

The Claimant was a 15-year-old who was injured as a pillion passenger when his uncle (aged 16) driving the motorbike collided with another car after driving through a red traffic light. The purpose of the journey was to take the claimant to hospital after injuring his ankle. 

Post-accident, it was established that the motorbike had been stolen a few days prior to the accident, but both the claimant and his uncle (first defendant) denied knowledge of the same.

The defendant had the burden of proof that the claimant had actual or blind eye knowledge that the bike was stolen or unlawfully taken and, if proven, would trigger the operation of the illegality defence.

It was not a case where there were many contemporaneous documents relevant to the circumstances of the case and/or the claimant’s credibility. Therefore, the claimant’s evidence in the witness box became the ultimate basis upon which the judge could assess credibility.

Judgment

The defendants were unable to prove that the claimant had knowledge or reason to believe that the motorbike was stolen or unlawfully taken. Had they done so then:-

• it would have relieved the second defendant from any liability under Section 151 of the RTA as it would be considered an excluded liability under Section 154(4); and
• the MIB would not be liable to the claimant following judgment as an excluded liability under the Uninsured Driver’s Agreement.

Driving through a red traffic light was clearly dangerous driving (S2 RTA 1988) but there was no evidence that the claimant had actually encouraged or intended the dangerous act. Therefore, the facts did not amount to a joint enterprise of dangerous driving.

Notwithstanding that the claimant had requested his uncle to take him to the hospital for medical treatment, which was the reason for the journey on the motorbike, the judge found that the claimant had not caused the Section 143 RTA offence.

Conclusions

This case highlights the evidential difficulties faced by insurers mounting the illegality defence where there is a lack of any documentary evidence in support. In these circumstances, the default position by a trial judge is inevitably to make a determination of the facts based on his impression of the claimant as a witness, as was the case here.