A Hampshire company has been fined £270,000 for making 22 million nuisance calls.
Basingstoke-based company Media Tactics made automated marketing calls ranging from PPI and personal injury claims to debt management.
It is one of the highest fines the Information Commissioner's Office (ICO) has issued for nuisance calls.
Such calls can only be made to people who have agreed to receive them.
The company found they did not have the necessary permission to make the calls and were therefore operating against the law.
The investigation by the ICO was sparked by 182 complaints from consumers.
Media Tactics told the ICO that the data had been bought from other firms and they believed the people on the lists had consented to such contact.
The phone numbers were sourced from a number of websites including discount, prize draw, pay day loan and insurance broker websites.
Users had agreed to their details being shared with third parties.
However, the investigation found that the privacy notices displayed on the websites were generic and unspecific.
The ICO therefore found that the consent was not adequate enough.
In addition to the fine, the company has been issued with a legal notice compelling it to stop making nuisance calls.
Failure to do this may result in court action.