Knowledge Hub | Articles

07 June 2013

Legal Eagle: Can I challenge a police breath test?

Legal Eagle is a regular column from Buckinghamshire solicitors B P Collins. If you have a legal problem you’d like advice on, please email and the team will select one question to answer in each column. The B P Collins team can help with a wide range of issues, including family and matrimonial, property matters, employment law, disputes at home or at work, wills and probate and business law.

Mr H faces losing his job after a police breath test showed he was over the legal limit for driving. He disputes the result and wants to know if he can do anything about it. Litigation partner, Matthew Brandis, at Gerrards Cross-based law firm B P Collins LLP, explains his options.

Q. I had a small glass of wine during a lunch meeting and was driving back to the office when I was stopped by the police and asked to provide a breath test. I was horrified to find I was over the legal limit as I would never knowingly drink and drive. If I am disqualified, I will lose my job. Can I challenge the police measurements of my alcohol level?

A. The legal limit is 80mg of alcohol in 100ml of blood. As you have found out though, there is no hard and fast rule as to how much alcohol would provide these readings – it will depend on your metabolism and body mass, whether food was consumed at or around the same time and how long it was between your drinking and getting behind the wheel.

Given your positive reading, you need to think back to when the test was taken. If you had blood or urine tests at the police station, then before you left, you should have been told that you were entitled to one of the two samples taken. This would allow you to have your own tests carried out by an expert.

If a breath sample was taken at the police station, then again you should have been given a print out of the result. You could appoint an expert to consider the reading against evidence of the alcohol you consumed, and also to ensure that the correct procedures were followed.

It’s not easy to challenge the results of a police alcohol test. However, the law on excess alcohol is highly technical and there can sometimes be room for investigation into whether or not the prosecution process was carried out correctly.

If the challenge is unsuccessful, then as you have already recognised, there is a minimum period of disqualification for driving with excess alcohol. This is 12 months, although it can be reduced a little (not less than three months) if you agree to attend an approved drink driving awareness course, provided the court offers you the opportunity to do so.

There are some circumstances in which you can ask a court not to disqualify you, but these focus more on the offence itself, rather than the effect disqualification would have on your life. For example, if you drove because an emergency situation arose, this might be considered a special reason.

For expert legal advice on motoring offences, please call Matthew Brandis on 01753 279039 or email

This advice is written in general terms only and should not be relied upon in individual cases where specific legal advice will be required. The writers accept no liability for any direct or indirect loss arising from any reliance placed on replies.

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Phone: +44 (0) 1753 889995


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