At the launch of his annual report in London, Richard Thomas, the Information Commissioner, said: "Over the last year we have seen far too many careless and inexcusable breaches of people's personal information.
"The roll call of banks, retailers, government departments, public bodies and other organisations which have admitted serious offences is frankly horrifying."
The report reveals that the ICO received almost 24,000 enquiries and complaints concerning personal information in the past year.
The commissioner said that the public's awareness of data protection rights had risen to a record level of 82% with more people understanding the need to handle personal information appropriately.
The highest number of complaints was about internet firms, followed by banks, direct marketing organisations and telecoms companies.
Last month the ICO found Littlewoods and mobile operator Orange in breach of the Data Protection Act.
In one case, Littlewoods continued to send a customer marketing material despite her attempt to stop it using her personal data for marketing purposes.
In the other case, Orange call-centre staff were allowed to share usernames and passwords when accessing the company IT system.