The police have developed an algorithm to measure the likely quantities of drugs supplied by a particular defendant. The use of the algorithm as evidence was recently challenged in the Court of Appeal. However, the court ruled that it was “reasonable for the Recorder to consider the results” when sentencing.

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What does the algorithm do?

The algorithm was designed by a police officer of the Metropolitan Police Service, in collaboration with a company called Forensic Analytics. It uses mobile phone data to quantify the volume of drugs supplied by a defendant.

Challenge in the Court of Appeal

The algorithm was recently used in court as part of the prosecution’s evidence. It was then referenced by the Recorder (judge) during his sentencing remarks. The use of the algorithm was challenged by the defence after sentencing had taken place. However, the Court of Appeal upheld the decision, stating that:

“In determining that the category 2 threshold was met, the Recorder did not regard himself as hidebound by the algorithm. His sentencing remarks make plain that he treated it only as a guide. He recognised the fact-sensitive nature of the sentencing exercise, putting the results of the algorithm into context. His slip in relation to the number of customers was immaterial. If the applicant had wanted to challenge the assumptions made by the prosecution evidence, he could and should have produced evidence of his own. In our view it was reasonable for the Recorder to consider the results of a cautiously operated algorithm as a fair way of approaching the Guideline.”

What does this mean for future case?

The Court of Appeal’s ruling sheds some light on the use of the algorithm during criminal proceedings.

Firstly, we can deduce that the algorithm can only be one of the factors considered by the judge during sentencing. It is therefore unlikely that there will be any substantial shift in the way that sentences for drug supply offences are decided.

Secondly, we can conclude that the assumptions produced by the algorithm are open to challenge in court. As per the ruling, the defence must present their own evidence to counter the numbers suggested by the prosecution.

Given the algorithm’s infancy, and its potential impact on drugs supply convictions, we expect further case law to develop on this in the coming years.

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