What Happens If You’ve Failed a Breath Test

You just failed a roadside breath test

If you’ve been pulled over while driving and you fail a breathalyser test, you’ll be arrested and taken to the nearest police station.

At the police station, officers will ask you to provide two evidential specimens of breath for analysis by an official testing device. Usually breath testing is used, but if there is a valid medical reason as to why breath specimens cannot be supplied, blood or urine specimens can be required instead.

Once you’ve provided the breath samples, the lower reading will be used as evidence in a prosecution, as long as it’s over 40ug/100ml of breath (the legal limit is 35ug/100ml of breath). The other reading will be disregarded.


Before giving the evidential samples an officer should ask you:

If you have, in the previous 20 minutes, consumed any alcohol, used a mouth spray or mouthwash, taken any medication, eaten anything, inhaled anything, taken anything else or brought up any stomach contents. If you’ve done any of these things, then another 20 minutes should be left before you give the samples.

Giving the samples

Once you’re ready to give the samples, an officer will explain what you’re about to do and how the samples will be used. You’ll also be warned that failure to provide the samples will make you liable to prosecution and asked if you agree to provide the samples.

If you don’t agree, you’ll get a final warning and request. If you still refuse the breath test the officer will ask if there are any medical reasons preventing you from complying. It’s always best to comply and then engage legal experts like drinkdrivesolicitor.com to ensure the best outcome for you.

If you agree, testing will commence and you’ll be talked through the procedure. If you’re unable to complete the procedure, you’ll be asked again if there’s a medical reason for your inability to give a sample, like asthma, for example. All official testing devices have a three-minute window to collect the samples.

Medical reasons

If you explain that there are medical reasons preventing you from giving a breath sample, the officer can request a blood or urine sample instead.

If you give no medical reasons but still refuse to comply, you will be charged with failing to provide a specimen for analysis, an offence which also carries mandatory disqualification on conviction.

The evidential breath test results

What happens next depends on your results:

  • 35 or below and you won’t be charged;
  • Between 36 and under 40 (the prosecution limit is 40) – you’ll probably be released without caution or charge, unless you were involved in a serious accident and “back calculation” is being considered to determine your blood alcohol at the time of the offence/accident, and
  • 40 and above, you will be charged.

You’ll be given a printed copy of the breath test if your results are to be used as evidence in a drink-driving prosecution.