If you are pulled over for a driving offence, then the police officer may ask you to provide a specimen for analysis. You will normally be asked to provide a breath sample at the road side. In some circumstances you may also be asked to provide another specimen at the police station.
Failing to provide a specimen for analysis when requested to do so is a criminal offence and you may be prosecuted for this in addition to any other offence that you are alleged to have committed. If you have a reasonable excuse for not being able to provide a specimen for analysis, then you may be able to use this as a defence.
If you or your legal team is able to provide a reasonable excuse for failing to provide a specimen for analysis, then the onus falls on the Prosecution to disprove this excuse beyond reasonable doubt. To put things simply, if you can show that you had a genuine reason for not providing a sample when asked for one, then you should not be convicted of this offence.
It is up to you and your lawyer to identify the genuine reason why you did not provide a sample when asked to do so. Examples of genuine reasons which have been used in the past include a genuine phobia of needles that prevent a blood sample being taken, or a severe breathing disorder which prevents an adequate breath sample from being taken.
When you are asked to provide a sample for analysis, the police officer must explain the consequences of failing to provide a sample. If they do not explain this to you, or if the explanation is given at a time when you are unable to understand their warning, then you may be able to use this as a reasonable defence. For example, if you were having an anxiety attack or a panic attack when your rights and responsibilities were outlined to you, then you may not have been able to fully understand the consequences of your refusal.
If you have any mental health issues which may have affected your ability to provide a sample, you should also mention these to your driving offence solicitor.