It appears that the authority sent out the message to 4,000 local companies, inviting their comments on certain issues. According to ZDNet, some businesses received the same message at least 20 times.
The Cambridgeshire Police Authority apparently characterised the e-mail as a "new method of consultation" that failed due to a "major technical error, or corruption of the original files", and apologised for "any inconvenience" caused to the recipients.
The authority reportedly said it "did not believe" it breached data protection legislation, because the names of the recipients were taken from a public list.
In a separate incident, Tower Records has apologised to millions of UK and US consumers whose personal data were exposed on its web site due to a "programming error." The error apparently allowed internet users to view a database with customer orders dating from 1996 to last week, including customers' home and e-mail addresses, phone numbers and details of what products were purchased.