The "technical issue" led to some raw data belonging to the constabularies being included within files produced in response to FOI requests.

The data included information held on a specific police system and related to crime reports for a range of offences, including domestic incidents, sexual offences, assaults, thefts and hate crime.

In a joint statement, the forces said the data, issued between April 2021 and March 2022, was hidden from anyone opening the files.

However, they admitted it should not have been included.

"Strenuous efforts have been made to determine if the data released has been accessed by anyone outside policing. At this stage, we have found nothing to suggest that this is the case," the forces said in their statement.

Assistant Chief Constable of Suffolk Police, Eamonn Bridger, said: "We would like to apologise that this incident occurred, and we sincerely regret any concern that it may have caused the people of Norfolk and Suffolk.

"I would like to reassure the public that procedures for handling FOI requests made to Norfolk and Suffolk constabularies are subject to continuous review to ensure that all data under the constabularies' control is properly protected."

The forces said they will notify all 1,230 people whose data has been breached.

This will be done via a letter, over the phone, or, in some cases, face-to-face, depending on "what information was impacted and what support is required"

Officers expect this process to be completed by the end of September this year.

"If members of the public are not contacted by the constabularies, they do not need to take any action," the forces said in a statement.