an Email

How DNA testing can assist in Drink Drive offences.

< Back to News Articles Summary

DNA might not seem an obvious tool to assist in Drink Drive cases; however in two cases it has proved to be decisive.

Case one – Failure to provide.

When an individual fails to provide a breath specimen for analysis the operator of the Evidential Breath Testing Device is instructed on the form MG DD/A (the Drink Drive procedure form)

 “In any case of a FAILURE TO PROVIDE, when an attempt was made to use the instrument, the mouthpiece should be packaged and retained as a possible exhibit and to be available for forensic examination if required”.

This is to ensure that there has not been a fault with the mouthpiece which had led to the failure of the suspect to provide the breath sample.  Ordinarily the mouthpieces are bagged up and kept for examination.  However, in one case the CCTV footage of the procedure showed the officer threw the mouthpiece into a waste paper bin in the corner of the room where the machine was situated.  The officer then realised his mistake and went to the bin where he could be heard to rummage through a number of items, presumably including other mouthpieces, before he retrieved a mouthpiece and bagged it.  As there was doubt that the correct mouthpiece had been retained, my colleague at Formedecon, Mrs Linzi Howarth, swabbed the end of the retained mouthpiece and a reference sample was obtained from the defendant.   DNA testing revealed that there was DNA present from the individual who had used the mouthpiece but that this DNA was not from the defendant.  This showed conclusively that the incorrect mouthpiece had been retained and the correct mouthpiece could not be examined.  The Court found that drink driving procedure had not been followed correctly.


Case two – straight forward blood sample

An individual “out of the blue” was banned from driving after a charge of driving with excess alcohol.  He claimed he knew nothing of the charge or conviction, having been convicted in his absence after a blood sample in his name had been analysed and found to be over the limit for alcohol.  He also claimed that he had never provided a blood sample for analysis, nor had he been stopped by the police in the first place.  Understandably the gentleman wanted to appeal his conviction.  After a number of requests to the Crown Prosecution Service via our instructing Solicitors, part of the prosecution blood sample was made available. Once again my colleague Mrs Howarth, took a sample of the blood and a reference sample from the appellant, for DNA comparison.  The blood sample was discovered not to have been from the appellant.  An unknown individual had given false details at the time of their arrest and had “escaped” the Drink Driving Charge (although now their DNA was on file).  The appellant won his appeal.

By Andrew Stephens BSc. C.Biol. MSB. MRSC. FCSFS.

Alcohol expert at Formedecon Ltd

Used by #1 Motoring Solicitors to ensure the best for the clients.