4 Why do these perceptions matter?
Our research findings show that trust influences people’s willingness to collaborate with police investigations, meaning that they might not come forward with evidence critical to resolving the case. For instance, they may have a video of a crime on their mobile phone but are unwilling to give it to the police for fear the police would find incriminating information about them unrelated to the crime. This lack of sharing potentially relevant evidence can severely impact case investigations and outcomes (Kaplan-Damary et al, 2025; Ingemarsson et al., 2024).
Some people, and especially those from communities that are rarely heard, don’t fully understand how the CJS works. At the same time, they are often more affected by it, sometimes as victims of crime. For those who do have experience with the system, their understanding often comes from past contact. Unfortunately, this experience can lead to distrust, especially if they felt they were treated unfairly or that the system was biased against them.
Many people said they want to help the police, for instance by sharing evidence, because they believe it’s the right thing to do. But, they worry about how this might affect their relationships within their community and fear they could be seen as betraying their own.
When people were shown a video of someone sharing footage of a crime with police to help an investigation, 87% (out of approximately 250 people) agreed this was the right thing to do. However, when asked if they would allow police to access their phone directly, most were uncomfortable with this. They preferred to keep control and share photos or videos themselves, for example by email.
This helps explain the wider issue of criminal cases not having enough evidence. Across England and Wales, the number of cases leading to a criminal charge has fallen. Between 2016 and 2023, charging someone for a crime dropped significantly (from 11.1% to 4.6% for crimes involving a victim), though there has been a small increase charging rates in 2024.
A key challenge to charging someone with a crime are ‘evidential difficulties’. This means there is not enough solid evidence even if a suspect is known. It could be due to lack of sufficient physical evidence or because victims or witnesses are unwilling to support the case.
