Police Procedure Errors in Drink Driving

Drink driving offences in England and Wales are prosecuted under strict legal rules set out in the Road Traffic Act 1988 and governed by police procedures designed to ensure fairness and accuracy. While drink driving is treated seriously by the courts, cases can be weakened - or even dismissed - when police fail to follow correct procedure.

Errors can occur at various stages of a drink driving investigation, from roadside breath tests to evidential sampling and custody procedures. Understanding these potential failures is essential for anyone facing an allegation of drink driving.

Why Police Procedure Matters in Drink Driving Cases

UK drink driving prosecutions rely heavily on scientific evidence and lawful police conduct. Officers must demonstrate that they acted within their legal powers and followed prescribed procedures throughout the investigation.

If correct procedures are not followed, the court may question the reliability of the evidence or the fairness of the process. In some cases, this can result in evidence being excluded or given less weight, significantly affecting the prosecution’s case.

Roadside Breath Test Errors

Police may require a roadside drink driving breath test if they have reasonable grounds to suspect that a driver has consumed alcohol. However, this power must be exercised lawfully. 

Common procedural issues include:

• Administering a test without proper legal grounds
• Failing to give clear instructions to the driver
• Using a device that is not Home Office approved
  

A roadside breath test is not evidential. It simply provides grounds for arrest. If the roadside procedure is flawed, it may cast doubt on whether the arrest itself was lawful.

Errors in Evidential Breath Testing at the Police Station

Once arrested, a suspect must be taken to a police station to provide an evidential breath sample. This is the stage at which alcohol levels are formally recorded for court purposes.

UK police must follow a strict process, including a mandatory observation period of at least 20 minutes before testing. During this time, the suspect must not eat, drink, smoke, or regurgitate, as this could affect the accuracy of the result.

Failures at this stage may include rushing the test, failing to observe the suspect properly, or not explaining the testing procedure and legal implications. Such errors can undermine the reliability of the breath evidence.

Blood Sample Procedure Errors

Blood samples may be required if a breath test cannot be provided or if there are medical reasons preventing breath testing. The procedure for blood sampling is tightly regulated.

Police must obtain informed consent and ensure that the sample is taken by a registered medical professional. The drink driving blood test must then be correctly sealed, labelled, stored, and transported. One part of the sample must also be offered to the suspect for independent analysis.

Any failure in this process - whether through improper consent or mishandling of the sample - can seriously weaken the prosecution’s case. 

Urine Sample Errors in Drink Driving Cases

Although urine samples are less commonly used today, they are still permitted under UK law in certain circumstances.

Procedural problems often include:

• Failure to follow the correct two-sample process
• Inadequate supervision during sample provision
• Incorrect timing between samples

If drink driving urine testing procedures are not followed precisely, the resulting evidence may be unreliable.

Police Errors in ‘Drunk in Charge’ Cases

Drunk in charge offences do not require proof that the person was driving, but it does require evidence that they were in charge of a vehicle while over the legal alcohol limit.

Police errors can arise where assumptions are made without sufficient evidence, such as relying solely on possession of car keys or proximity to a vehicle. Officers must consider whether there was a realistic likelihood of the individual driving.

Errors in ‘Unfit Through Drink’ Allegations

Unlike offences based on exceeding the legal alcohol limit, unfit through drink cases rely heavily on officer observations.

Problems often arise when:

• Observations are poorly recorded
• There is no clear explanation of how alcohol impaired driving ability
• There is insufficient supporting evidence
  

Courts scrutinise these cases closely due to their subjective nature. 

Custody and PACE Procedure Failures

Once in custody, police must comply with the Police and Criminal Evidence Act 1984 (PACE). This includes proper cautioning, accurate custody records, and ensuring access to legal advice.

Failure to follow custody procedures can result in evidence being excluded and may significantly strengthen a defence.

How Police Procedure Errors Affect Drink Driving Cases

Police errors do not automatically result in acquittal, but they can:

• Undermine the reliability of key evidence
• Raise questions about the fairness of the investigation
• Provide strong grounds for legal challenge
  

An experienced drink driving solicitor will examine every stage of the police investigation for procedural failings.

Need Help with a Drink Driving Charge?

MAJ Law’s specialist solicitors have extensive experience defending drink driving cases, including those where police procedure errors may affect the evidence against you. 

We can review the conduct of the police and the handling of breath, blood, and urine tests, advise on potential defences such as procedural errors or inaccuracies in evidence, and represent you throughout the legal process to achieve the best possible outcome. 

Don’t face a drink driving charge alone contact M.A.J Law today for expert advice and a strong defence.