Hip Flask Defence in Drink Driving Cases

What Is the Hip Flask Defence?

The hip flask defence refers to a situation where a driver argues that the alcohol detected during police testing came from alcohol consumed after driving had ended.

For example, this may arise where: 

• A driver consumes alcohol after arriving home 
• Alcohol is consumed after a road traffic collision 
• Alcohol is consumed before police arrive at the scene 

In these circumstances, a driver may argue that they were not over the legal alcohol limit while driving, and that the alcohol level detected during testing resulted from post-incident drinking. 

However, raising this defence does not automatically prevent prosecution. The court will examine the evidence closely to decide whether the explanation is credible.

The Law on Drink Driving in England and Wales

Drink driving offences are governed primarily by the Road Traffic Act 1988. 

Under this legislation, it is an offence to: 

• Drive or attempt to drive while above the prescribed alcohol limit 
• Be in charge of a motor vehicle while over the limit 

The prescribed limits in England and Wales are currently:

• 35 micrograms of alcohol per 100ml of breath 
• 80 milligrams per 100ml of blood 
• 107 milligrams per 100ml of urine 

In drink driving cases, the prosecution may rely on the alcohol level shown in the evidential specimen.

Evidence Used in Hip Flask Defence Cases

Courts may rely on several types of evidence when assessing drink driving cases.

Breath Test Evidence

Roadside breath tests and evidential breath tests are often the first indication of alcohol levels.

Police powers to conduct breath tests are set out in legislation and explained by the Crown Prosecution Service guidance on drink driving offences. 

Blood or Urine Samples

Where breath tests are not possible, or where another type of specimen is required, police may request blood or urine samples.

These samples are analysed to determine alcohol concentration at the time of testing. 

Expert Toxicology Evidence

Where the hip flask defence is raised, expert forensic evidence may be necessary.

A toxicology expert may assess: 

• Alcohol absorption timelines 
• Blood alcohol levels at the time of driving 
• Whether the driver could realistically have been under the limit while driving 

Risks of Relying on the Hip Flask Defence

Although post-incident drinking is recognised in law, it is not easy to establish.

Courts will carefully scrutinise claims of post-incident drinking. 

Potential difficulties include: 

• Lack of supporting evidence 
• Inconsistent statements 
• Scientific calculations contradicting the defence 

If the explanation is not accepted, the court may conclude that the driver was over the legal limit while driving.

Sentencing guidance for drink driving offences can be found through the Sentencing Council for England and Wales, which outlines penalties including driving disqualification, fines, and potential imprisonment.

How Defence Solicitors Challenge Drink Driving Evidence

Defending a drink driving allegation often requires detailed examination of the prosecution case.

A defence solicitor may consider: 

• Whether police followed correct procedures 
• Accuracy of breath testing equipment 
• Timing of alcohol consumption 
• Scientific alcohol calculations 
• Reliability of witness evidence 

Where post-incident drinking is alleged, expert evidence may be required to analyse whether the alcohol level detected could be explained by drinks consumed after driving.

Each case turns on its specific facts and evidence, which is why legal advice is important when facing an allegation of this nature.

Speak to a Criminal Defence Solicitor

Drink driving allegations can carry serious consequences, including disqualification from driving, financial penalties and possible imprisonment.

If you are facing an investigation or prosecution involving allegations of drink driving, obtaining advice from experienced criminal defence solicitors is essential. Early legal guidance can help ensure the evidence is properly assessed and that any available defence is carefully considered.