This is the official line ( 'The Information Commissioner’s Office is the UK’s independent authority set up to uphold information rights in the public interest, promoting openness by public bodies and data privacy for individuals'
http://www.ico.gov.uk/global/faqs/privacy_and_electronic_communications_regulations_for_the_public.aspx
Q: I am receiving unsolicited marketing emails. What can I do about these?
The Privacy and Electronic Communications Regulations lay down rules for organisations sending unsolicited marketing by electronic means. The rules are different depending whether the recipient is an 'individual subscriber' (eg Jonsmith@yahoo) or a 'corporate subscriber' (eg Jonsmith@ico).
The regulations say that organisations must have prior consent to send unsolicited marketing material by electronic mail to individual subscribers, unless they have obtained the details during the course of a sale, or negotiations towards one, and they give you the opportunity to object in every message. If you are an individual subscriber receiving unsolicited marketing by electronic mail, and the organisation hasn't stopped even though you've tried to opt out, you can complain to the ICO.
If you are a corporate subscriber the prior consent rule does not apply. Marketing communications should still identify the sender and provide a valid address. Depending on the information the company holds about you, a corporate subscriber may also have rights under the Data Protection Act.
Read our topic guide about spam email