Visit any police website across the UK and you will be met with rows of faces – each one belonging to the victim of a crime that has yet to be solved. As of March 2022, the last full year for which we have statistics, only 5.6 per cent of crimes in the UK secured a conviction. At the same time, Home Office figures show sex offences hit a record high, homicides were up 25 per cent, and 2.4 million cases were closed due to “evidential difficulties”, without police ever identifying a suspect.

There is a relatively nascent technology that has potential to reverse such trends, called forensic or investigative genetic genealogy (IGG). It’s been both lauded a success and had its legality called into question, and as officials decide its fate, we look at where the battle lines have been drawn.

Since the first at-home DNA kits hit the market in 2007, more than 26 million people have uploaded their DNA online. The early tests revealed interesting but not particularly...