Driving Whilst Unfit Through Drink

M.A.J Law is a market leading motoring defence firm. We regularly challenge allegations of driving whilst unfit. This offence, found under section 4 of the Road Traffic Act, requires the CPS to prove that you were impaired through alcohol. Impairment alone is not sufficient. We would be pleased to discuss your case in detail free of charge.


We can help you with:

  • Understanding 'impairment'
  • Defending an allegation
  • Next Steps

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Driving or attempting to drive whilst unfit through drink

Breath / Blood / Urine - Section 4 of the Road Traffic Act 1988 

Driving whilst unfit through drink is a serious offence. If convicted, it will carry a mandatory driving disqualification of 12 months. If the level of impairment is severe, you could be sent to prison. Take a look at the Driving Whilst Unfit Sentencing Guidelines below. 

If the police are alleging that you were unfit, it is crucial that you consider your options prior to the first court hearing, as it is possible that you have been charged with the wrong offence. Due to the similarities between this offence and drink driving, the police often get confused between the two. If you provided a breath, blood or urine sample over the prescribed limit at the police station, you should be charged with drink driving, not driving whilst unfit. 

You may not know the results of your test because the wording of a Section 4 charge does not include the level of alcohol. Instead it simply says "whilst unfit through drink"

Of course, it is always open to the police to charge you with driving whilst unfit even if you were over the limit. But there is little sense in doing this as it is much harder to prove that you were ‘impaired’ than proving that you were over the limit (as one is subjective whilst the other isn't). In the majority of Section 4 cases that M.A.J. Law defend, the CPS will realise the mistake made by the police and attempt to amend the charge to drink driving. However, this may not be as simple as it sounds, particularly if trying to amend a charge after the first court hearing. Remember that the CPS has only 6 months to lay charges. If they spot the error after this time, they should not be allowed to change the charge (Section 127 Magistrates' Court Act). The CPS are then stuck with a Section 4 offence which it cannot prove (because it cannot prove impairment). An inaccurate or defective charge can lead to a failed prosecution, so it is crucial that we don’t ‘tip off’ the CPS. 

If you think you may have been charged with the wrong offence, please call us immediately. The earlier the team at M.A.J. Law can intervene, the earlier we can safeguard your position and identify a defence strategy.

Proving that you were ‘impaired’

Remember that evidence of a car accident does not prove impairment, especially if the location where the accident happened is an 'accident hot-spot'. A Freedom of Information Request will tell us how many accidents have occurred at the same location. 

To achieve a conviction for a Section 4 offence, the CPS must prove that you were ‘impaired’ as a result of the alcohol consumed. The test for impairment under the statute is the ability to “drive properly”. To establish this, the CPS may need evidence that;

  • You were unsteady on your feet
  • Your speech was slurred
  • You smelt of intoxicants
  • Your eyes were glazed
  • You provided a positive breath sample
  • Your driving was erratic

Many of the factors above could be established by presenting evidence to show that you failed a Field Impairment Test. In our experience, the police don't always carry out Field Impairment Tests. Even where they do, they often get them wrong. 

The Field Impairment Test

Sometimes referred to as a 'roadside impairment test' or a 'fitness impairment test', this exercise is designed to assess the level of a person's impairment. 


The test includes a pupillary examination, the modified Romberg balance test, the walk and turn test, the one leg stand test and the finger and nose test. The officer completing the test must have been approved for the purpose of administering such tests. If the officer is not trained to conduct the procedure, or approved, the test results may be invalid. If we're acting for you we can request an authorised copy of the officer's training certificate. The CPS regularly fail to produce training records when asked. 

Whilst conducting the Field Impairment Test the officer must record the results in a document called the MGDDF. This stands for the the Manual Guidance for Drink Driving Pro Forma F - and contains the instructions the officer must follow. 

Impaired “through drink”

The difficulty for the CPS arises when trying to prove that any impairment was as a consequence of any alcohol consumed. What if you were impaired because you were tired, or because of a drug that had been consumed, whether illegal or not? Many people take medication that may cause some minor impairment. How do the police prove that alcohol-only was responsible for the impairment?

The obvious way to prove that you were impaired as a result of alcohol consumption is to rely on the breath, blood or urine results (which will presumably be positive). However, the CPS may not be able to use these results if the procedure when taking the sample was not conducted correctly. Despite this offence being very different to drink driving, many of the same defences apply. You can read more about these defences here.  


The minimum penalty for driving whilst unfit is a 12 month disqualification. The maximum penalty is 6 months imprisonment. The court has the option to impose an immediate disqualification up to 36 months and a fine up to £5,000.00. The court also has the option to impose a community service order (i.e. unpaid work or a curfew).

The penalty imposed will depend upon your level of impairment. It is for this reason that you should always take the opportunity to consider the evidence against you (which may not be provided on the first court date). You may dispute the facts alleged by the police (who often exaggerate the level of impairment). This, of course, would have a direct bearing on the penalty imposed if you pleaded guilty. Our team have the technical expertise to secure your acquittal.


Driving whilst unfit through drink

Sentencing Guidelines 

Impairment Starting point Disqualification Disqualification (2nd offence)
Low-Moderate Band C fine 12 – 16 months 36 - 40 months
Moderate Band C fine 17 – 22 months 36 - 46 months
Moderate-High Community Service 23 – 28 months 36 - 52 months
High 12 weeks custody 29 – 36 months 36 – 60 months

Impairment Guidelines 

What is low, moderate and high impairment? 

Impairment level Description
Low No obvious or tell-tale signs of impairment 
Low - Moderate Slight impairment (e.g. red eyes)
Moderate Some impairment (e.g. speech slurred, confusion)
Moderate - High Obvious impairment 

Any person convicted of drink driving will receive a fine, community service or prison sentence. The type of penalty depends upon the circumstances of the office and, of course, the level of impairment. You would also receive a mandatory driving disqualification. The chart above is used by the magistrates when sentencing for Section 4 offences. You can also use our drink driving ban calculator to work out the likely penalty. 

If you avoid a conviction, you will not be disqualified. 

We would be happy to discuss your case in detail with you, completely free of charge. You may not realise that you have a full defence to the allegation. Please call us or request a free call back.