A police trial of facial recognition equipment at Notting Hill Carnival led to around 35 false matches and one wrongful arrest, according to Sky News.
Although the technology did correctly match one face at the carnival, the person was already going through a justice system process and shouldn't have been on the suspects database.
It is thought that the system identified the individual as being wanted for rioting but they had actually already been arrested in between the database being compiled and the carnival taking place.
Sources also claim that five others were asked by police to prove their identity, as the system had identified them as suspects and if they hadn't been able to prove their identity they would have been wrongfully arrested too.
Silkie Carlo, technology policy officer from human rights group Liberty, claimed the trial was a "worryingly inaccurate and painfully crude facial recognition operation."
Carlo also claimed leaders of the project thought the wrongful arrest was a "a resounding success, not a failure."
Sky News previously reported that there are hundreds of thousands of facial recognition images held by police which are of innocent people.
The High Court also ruled in 2012 that holding these pictures is against the law.