From here:
http://www.ico.gov.uk/complaints/data_protection.aspx
Before you complain to us
First, tell the organisation concerned and give it an opportunity to put things right. Many data protection problems can be solved quickly without us getting involved. You can call our helpline on 08456 306060 or 01625 545745 for advice to help you to solve the problem.
What happens if I cannot solve the problem myself?
If you have contacted the organisation about the problem but have been unable to solve it, we may be able to help.
If necessary, we will look into your complaint. If we think the law has been broken, we can give the organisation advice and ask it to solve the problem. In the most serious cases we can order it to do so.
We cannot award you compensation or punish an organisation for breaking the law. Our main aim is to get the organisation to change the way it works so that it handles personal information properly in the future.
Supporting evidence
You will need to provide us with information in support of your complaint otherwise it may not be eligible for further consideration. Our complaint form explains the kind of information we need, but if you are unsure please call our Helpline on 08456 30 60 60.
Make your complaint - By post: If your supporting evidence is in hard copy, you can fill in the Word version of our complaint form, print it out and post it to us with your supporting evidence.
Data Protection Act complaint form (Word version for submission by post).
- By email: If all your supporting evidence is available electronically, you can fill in our our online complaint form.
When completing the form, please avoid using the following characters: <, >, %, ~, & or ^. These characters are currently blocked by our website for security reasons, and may prevent your form from being submitted.
Information included in the form and any supporting evidence will be sent to us by email. Please remember that email messages can be intercepted.
Data Protection Act complaint form (for submission by email).