Companies could be forced to disclose the information that held on staff if trade unions use new data protection rule to press the issue in the courts.

A new draft data protection code sets out legal standards to comply with the Data Protection Act in areas such as email surveillance and recruitment, and businesses have expressed concern about the "confusing and unworkable" code.

The TUC says the code is "incredibly useful" and would take action to force disclosure of information in tribunal cases and other circumstances.