A spam operation that bombarded the public with nuisance calls has been hit with a £350,000 fine by data privacy watchdogs.

The Information Commissioner's Office (ICO) served their highest fine ever after finding that Prodial Limited, a Brighton company operating from a residential property, generated an estimated £1 million turnover from more than 46 million unwanted cold calls.

Over 1,000 people informed the ICO of the automated calls that played recorded messages related to Payment Protection Insurance (PPI) claims. The complainants advised that they were called on a repeated basis with no option to opt out. The law states that companies can only make calls to people who have specifically consented to being contacted by automated marketing calls.

The ICO's investigation found that Prodial secured no consent and was using the calls to sell people's personal details to claims management companies.

Christopher Graham, the Information Commissioner, said: “This is one of the worst cases of cold calling we have ever come across. The volume of calls made in just a few months was staggering. This was a company that knew it was breaking the law. A company director admitted that once the ICO became involved, the company shut down. That stopped the calls, but we want to send a clear message to other firms that this type of law-breaking will not pay.”