Ambrose v Chester Magistrates Court: High Court quashes refusal of special reasons in spiked drink case

The Administrative Court has quashed a deputy district judge's refusal to find special reasons in a spiked drink case, holding that the correct authority was R v Cambridge Magistrates' Court, ex p Wong [1992] RTR 382 rather than Delaroy-Hall v Tadman [1969] 2 QB 208.

In R (Ambrose) v Chester Magistrates Court [2026] EWHC 1728 (Admin), handed down remotely on 9 July 2026, Mrs Justice Hill DBE allowed the claim on both grounds and remitted the matter to a freshly constituted bench. Rhys Rosser appeared for the claimant, instructed by Caddick Davies Solicitors. Hannah Squire appeared for the Crown Prosecution Service as interested party. The magistrates court did not attend and was not represented.

Background

The claimant was stopped in Chester in the early hours of 1 February 2025 and provided a roadside specimen reading 41 µg of alcohol per 100 ml of breath, against a prescribed limit of 35 µg. Evidential specimens at the custody facility read 42 and 43 µg. He was charged under section 5(1)(a) of the Road Traffic Act 1988 and pleaded guilty on the basis that his wine had been spiked.

At the special reasons hearing on 30 September 2025, Deputy District Judge Munir accepted the evidence of the claimant and of Ella Stewart, who admitted adding a shot of tequila to his glass without his knowledge. Agreed forensic evidence established that, absent the spiking, the reading would have been approximately 36 µg, below the 40 µg prosecution threshold established by Home Office Circular 46/1983.

The judge nonetheless declined to find special reasons. He held first that there was no room for the de minimis principle once the matter was before the court, applying Delaroy-Hall, and second that the claimant could not show that but for the spiking his reading would have fallen below the prescribed limit, an apparent application of Pugsley v Hunter (1973) RTR 284. A 36 month disqualification followed, alongside a fine, victim surcharge and costs. The judge subsequently declined to provide written reasons on the basis that the magistrates court is not a court of record.

The court's reasoning

The CPS conceded that the approach was wrong, a concession Hill J considered appropriate. She found the facts on all fours with Wong, where the applicant was unaware his cough linctus contained alcohol, his reading sat only just at the prosecution threshold, and there had been no bad driving. In both cases, but for the innocent additional intake, the reading would have fallen below the threshold for prosecution.

Delaroy-Hall was distinguished. It concerned blood rather than breath, predated the breathalyser regime and the 1983 circular, and did not involve spiking. It remains good law only for the proposition that, absent spiking, a marginal excess over the prescribed limit cannot constitute special reasons.

Nor was there any tension between Wong and Pugsley. The Divisional Court in Wong reached its conclusion expressly by reference to Pugsley, applying that principle to the breath testing context and confirming that special reasons may be established where the excess over the prosecution threshold, and not merely the prescribed limit, is attributable to the spiking. Reliance on Delaroy-Hall and on Pugsley without that gloss was an error of law.

Relief

The claimant sought substitution of the court's own decision under section 31(5)(b) of the Senior Courts Act 1981. The CPS opposed that course, and Hill J agreed it was not open to her. Section 31(5A) permits substitution only where the court below could have reached one decision alone, and that was not the position. Wong renders such circumstances capable in law of amounting to special reasons; it does not compel the finding. A residual discretion arises at the second stage, as R v Newton [1974] RTR 451 confirms, and evidence as to the manner of driving and the claimant's conduct at the roadside remained capable of bearing on whether he ought to have appreciated he was unfit to drive.

The disqualification and associated penalties were quashed. The special reasons question returns to a differently constituted bench on preserved findings that the drink was spiked, that the claimant did not know, and that the unspiked reading would have been 36 µg. No order for costs was made by consent.