North Yorkshire Police comes in top 10 for most data leaks
Figures compiled by Big Brother Watch show private information being shared or lost by hundreds of officers and staff members.
Ten data breaches are taking place in police forces in the UK every week, a new report suggests.
Hundreds of instances of inappropriate or unauthorised access to information and disclosure to third parties over four-and-a-half years were collated in research by Big Brother Watch.
Forces logged at least 2,315 data breaches involving officers or other staff between June 2011 and December 2015, according to the report.
They included 869 instances of inappropriate or unauthorised access to information and 877 of inappropriate disclosure of data to third parties, while 25 cases involved misuse of the Police National Computer.
North Yorkshire Police came in the top 10 forces with the highest number of breaches, with 98 within the four year time frame.
Three members of staff were dismissed.
Acting Chief Constable Tim Madgwick, said: "The figures are a reflection of how seriously we take breaches of the Data Protection Act.
"Given the confidential nature of police work and the millions of pieces of information that we hold, we will not tolerate the misuse of this information or anything that comprises it.
"All staff, officers and volunteers receive strict instructions about how information, and devices that hold this information should be stored, accessed and protected and if this is breached, we will take action."
Cleveland Police had 17 breaches during the 4 year time period, with five staff resigning over breach cases.
One staff member was sacked after passing details about a detainee to a relative.
A Cleveland Police spokeswoman said: "Cleveland Police takes data breaches extremely seriously and has a system in place for the reporting of such instances.
"There are robust controls in place to identify any accidental or deliberate breaches and where appropriate, action is taken against staff or officers who deliberately disclose information.
"The Force continues to seek ways of preventing accidental disclosures of data and has recently removed the ability for email addresses to be automatically completed, which can help in preventing an accidental disclosure of information.
"Any significant breaches are referred to the Information Commissioner."
Renate Samson, chief executive of Big Brother Watch, said: We trust the police to keep us safe. In the 21st century that is as much about keeping our data secure as protecting us on the streets.
"The revelation that the police are still committing 10 data breaches a week shows that work still needs to be done before we can be sure our personal information is safe in their hands.''