Challenging forensic evidence is crucial in criminal trials

As police investigate forensic experts it is ever more important to challenge scientific evidence

You may, or may not, know that I specialise in motoring law and that my practice has a particular emphasis on drink driving, drug driving and the associated offences. Because these offences usually require some scientific enquiry to be conducted to prove guilt, they frequently include forensic evidence and today I want to look at how courts deal with forensic evidence and challenges to it.

Let’s assume that somebody has been arrested for drink driving and, for whatever reason, the police have taken blood to assess how much alcohol is in his body. The prosecution will usually provide a document called an SFR1, which is a summary of the scientific examiner’s findings. It is not a document that is admissible itself, although it can be admitted if all parties agree. If a party does not agree to the summary being admitted then the prosecution ask the expert to produce an SFR2 document, which is a formal witness statement containing all of the experts findings and is in an admissible format. If the defence still do not agree to the evidence being admitted, then the prosecution should call their expert to give live evidence in court.

When the blood is analysed at the laboratory there may be several people involved in the process and each person will record their work, they do this to prove both to the court and for their quality control checks that the results are accurate. When the defence come to challenge the expert’s findings this is the material that the defence expert will require to consider whether the results are reliable or not.

Back to our suspected drink driver. The blood will have been taken by a healthcare professional before being sent to the lab by the police. Because alcohol levels rise over time a false high reading can be obtained if the blood is not stored properly so it is important to look at continuity of the specimen from the point the blood is taken to the point it is examined. Solicitors should be asking, where has the blood been, who has handled it and why? The vials blood goes into should contain a preservative but, as with all things, nothing is perfect so again it is important to check for any evidence that the preservative was missing or defective.

When the specimen arrives in the laboratory it will be handled by several people, so it is again important to ask who has handled it and what have they done with it? Luckily, scientists are very methodical people, so each person involved in the analysis will document their actions and those records can be used by a defence expert to consider whether the results are reliable or not.

Lots of things can go wrong in the testing procedure. For example, multiple blood specimens may go into certain pieces of equipment at the same time increasing the risk of cross-contamination. Where certain drugs are been hunted the expert will need to prepare other chemicals to assist in that process. When this happens laboratories should prepare two sets of chemicals from different suppliers and different batches to prevent errors occurring due to faults in a particular batch; however, often, for whatever reason, the lab cannot obtain chemicals from different suppliers and so rely on what they have, which may mean they use chemicals from the same supplier and same batch meaning that if there is a problem with that batch they will be unable to detect it in their results and so false high readings can go unnoticed.

Apart from errors there is also the risk of falsified results being provided by laboratories. How fanciful is that? Well there are currently 10,500 cases being reviewed as it is suspected that they may have had results falsified through manipulation by scientists at a laboratory owned by a company called Randox – a global forensic science company with teams in 145 countries. As part of that review, so far 50 cases have been discontinued and 40 motorists have had their convictions quashed. There are still another 7,500 cases to be re-examined. Three men are under investigation for perverting the course of justice.

It’s impossible to say why this happened or why errors in cases happen generally, but you may want to consider the words of Dorset police Chief Constable, James Vaughan, who said that there is a “chronic shortage” of scientific expertise and accredited laboratories in the UK. So, you may wonder whether overwork plays a part in corner-cutting that in turn leads to unreliable results.

The problem defence solicitors face is that neither courts nor the prosecution take challenges to expert evidence seriously – frankly nor to do some defence solicitors I’ve met.

Defendants are entitled, by law, to see the records produced by laboratories during the testing process; however, many judges treat requests for that information as if it were a time-wasting exercise designed to delay trials and upset the legal process. Prosecutors appear to take the same view, choosing simply to ignore requests for access to the material rather than dealing with it quickly and efficiently. By way of example, I recently acted in a case in which an expert required the lab notes. It took five court appearances before the material was finally provided and even then the Crown did not provide all of it. In another case, the judge clearly viewed the request as a complete waste of time and directed the Crown not to serve the material but only to allow our expert to view it if he attended the prosecution expert’s laboratory. The judge in that case was aware that the defendant was saying that he could not have exceeded the drug driving limit as he had never used that particular drug, which may lead you to question how fair that trial was ever going to be.

The result of this attitude is that people are convicted of offences when they shouldn’t be and that innocent defendants are put to far more expense than is necessary and it's worth remembering that the innocence tax means they won't get their money back even if they are acquitted.

The Randox case should be a wake-up call to everybody involved in the criminal justice system that experts are not infallible, that they do make mistake and even falsify evidence. It is only when that material is thoroughly challenged and examined by others involved in the process that errors are discovered and miscarriages of justice avoided. By the way, how was the Randox case uncovered? An anomaly in a drug driving case was reported to Randox who investigated and reported their staff to Greater Manchester Police!


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