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Physical Reasons

Asthma or other breathing problems

Mr Andrew Stephens is the author of a scientific paper looking at the minimum lung function requirements to provide a breath sample in the current generation of Evidential Breath Testing Instruments. Andrew is also familiar with the procedures involved in the taking of breath, blood and urine and the testing thereof. 

If you or your client believes that their asthma, or other breathing problems are the reason for their failure to provide a breath sample then this can be investigated.


Equipment Issues


Mouthpieces from Evidential Breath Testing Instruments (see opposite) should always be retained, by the Police, if an attempt to provide had been made, to allow a forensic examination, if required.  We have had a case were the CCTV shows the mouthpiece was thrown away but then turned up as evidence, our DNA expert was able to show the mouthpiece had been used but not by the defendant.

Machine Problems

Occasionally machines fail to accept a breath sample due to a machine fault.  Analysis of the three months of user logs pre and post test, together with the engineer's logs can usually find the cause if it is machine related.  


Failure to provide a sample due to anxiety or phobia


These cases fall into three groups, those involving breath, blood and urine.

We also have our Forensic Psychology team who investigate failure to provide a breath sample due to anxiety, failure to provide a blood sample due to needle phobia and failure to provide a urine sample due to shy bladder syndrome.

Blood Test
Stage Mist

Exposure to Chemicals

PAVA Spray

Research has show that exposure to PAVA spray can have a short term effect upon an individual's lung function.  If you or your client believe this is the reason for a failure to provide a breath sample when requested, then get in touch.

Chemical Exposure

Exposure to some chemicals can effect an individual's lung function.  If this is the problem that you believe caused you or your client to fail to provide a breath sample, then contact our drink drive experts.