We understand that the prospect of losing your driving licence can be life changing.

Being stopped by police and informed you have failed a drink-drive roadside test can be unsettling. However, this does not always result in disqualification from driving. The required procedure used by the police is complicated and technical, so it is imperative to have the support and advice from a specialist motoring lawyer from an early stage. They will check if any mistake was made by the police. If the error is significant enough, they can argue that you are not guilty at trial or persuade the prosecutor to drop the case before it reaches trial.


If you test positive for alcohol during a preliminary breath test or a preliminary impairment test, then you will be arrested. The police will then usually to take you to a police station to perform a further breath test on more precise equipment.


A conviction for an offence of driving with excess alcohol ‘or driving whilst unfit through alcohol ‘means that disqualification is mandatory, absent a finding that there are ‘special reasons’ to avoid or reduce the ban. A conviction for being ‘drunk in charge of a motor vehicle, with excess alcohol or when ‘unfit through alcohol’ will lead to a discretionary rather than a mandatory ban. The court will listen to mitigation on your behalf, before deciding whether to disqualify or not.

Frequently Asked Questions

  • What is a Preliminary Breath test?

    The police will conduct a preliminary breath test if they have a reasonable suspicion that the driver of a vehicle has consumed alcohol or has been involved in an accident. Police will typically use a roadside alcohol lion intoximeter breath test which will provide a pass/fail result. These tests usually do not provide specific breath readings. However, if they do give a reading, this can be argued to be evidence sufficient to prove that the driver was ‘over the prescribed limit’ if a case were brought to court.

  • What is the drink-drive limit?

    There are several methods the police have for testing the amount of alcohol in a person’s system. In the first instance, a breath test will be conducted, and the prescribed level in England and Wales is 35 micrograms (mg) per 100 millilitres (ml) of breath. However, most police forces will not prosecute cases unless the amount is at least 40mg per 100ml of breath. The police do sometimes take samples of blood or urine instead. The prescribed limit for blood is 80 milligrams per 100 millilitres, and for urine, it is 107 milligrams per 100 millilitres.

  • Do I have to be driving my vehicle dangerously or carelessly before the police can stop me?

    No. The police have the power to stop any vehicle on a public road for any reason. It is an offence to fail to pull over when asked to do so by the police.

    However, to perform a roadside breath test, or a preliminary impairment test, the police must have a reasonable suspicion the driver has consumed alcohol, which is still in their system and has committed a road traffic offence and/or was involved in a road traffic accident.

  • What is the difference between a preliminary breath test and a preliminary impairment test?

    A preliminary breath test will involve providing a sample of breath. A preliminary impairment test is a physical test that takes various forms and should be conducted according to an agreed code of practice. It may include performing actions such as ‘walking and turning,’ standing on one leg, a ‘finger to nose test, a’ pupillary examination and ‘The Modified Romberg Balance Test.’


    A qualified officer should perform the procedure, and the test could be excluded as inadmissible evidence if not administered correctly.

  • What if I have a medical problem that prevents me from providing a breath specimen?

    You will generally need to inform the police that you have a medical condition restricting your ability to provide a breath specimen. Following this, a medical examiner will decide if it is appropriate for you to provide either a blood or urine sample. The limit for blood is 80 milligrams per 100 millilitres, and for urine, it is 107 milligrams per 100 millilitres.

  • How is a person tested when suspected of drink driving?

    The usual procedure for taking formal evidential breath tests involves the police requiring an individual to provide two specimens of breath at the police station. The lower of the two samples will be the evidential test relied upon in court. A blood test can be taken by a medical practitioner/registered health care professional if they have indicated this is appropriate. If blood cannot be taken, then a sample of urine can be requested.

  • If the breath reading is between 40-50mg per 100ml, can I request a blood test?

    No. This used to be the case and was known as the ‘statutory option,’ but the law has since changed. The law change is the result of technological improvements in breath testing machines.

  • Can I challenge the Police alcohol test?

    Yes. breath, blood, and urine samples can be challenged in a number of ways. Conventional methods of doing this have included challenging the calibration of the testing equipment, having the personal blood or urine analysed by an expert, reviewing the test procedure for technical mistakes and/or reviewing any input from medical practitioners for potential issues.

  • If the level of alcohol in my breath is below the legal limit, can I be charged?
  • What if I had been drinking alcohol but was just sitting inside my car?

    If you have been sitting inside your vehicle intending to drive the car and you are over the drink-drive limit, then it is likely the police will charge you with being in charge of a vehicle having consumed an alcohol level which is over the legal limit.


    If there was no likelihood, of driving your vehicle while the level of alcohol in your system was above the legal limit, then you will have a statutory defence to the charge as per Section 5(2) of the Road Traffic Act 1988.

  • What is the difference between ‘driving with excess alcohol ‘or driving whilst unfit through alcohol‘?

    In order to prove the offence of ‘driving with excess alcohol ‘the prosecution must prove that the amount of alcohol in the sample provided exceeds a prescribed limit. This is a scientific measurement and there is a definite and clear figure to compare the sample against, depending upon whether it was breath, blood or urine. In order to prove the offence of ‘driving whilst unfit through alcohol’ evidence of impairment can be provided by a doctor who has examined the driver, without taking a sample. The court will often look at the totality of the evidence in order to decide whether the driver was unfit. This might include evidence about the manner of driving, the driver’s apparent physical state and anything the driver said about how much alcohol they had drunk.

  • Are there any defences to driving/being in charge of a vehicle while over the limit?

    Yes, there are a number of potential defences, but whether they apply will, of course, depend upon the individual facts of the case. Examples include that you were not driving, you drank alcohol that put you over the limit after you drove or duress of circumstances. If there was a technical defect with the machine or the police did not follow the procedure correctly, then this may lead to an application to exclude evidence from a trial. If excluded, this may mean that the crown would no longer be able to prove the case against you.


    While not defences, various other arguments could be advanced to seek to avoid a ban, after a guilty finding. These are called ‘special reasons.’ Examples include you only drove a very short distance, your drinks were spiked, or you only drove because of a genuine emergency.

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