Credit card provider NewDay has been fined £230,000 by the Information Commissioner (ICO) for sending more than 44 million spam emails.
The ICO was prompted to investigate the nuisance marketing following complaints from the public.
The investigation found NewDay had broken the law by not securing people’s agreement to be contacted by them.
NewDay instigated the sending of around 44.7 million spam emails promoting its financial products between April 2015 and January 2017.
The ICO said the company used other firms to send the emails to people who had subscribed to websites operated by those companies.
But an ICO investigation found NewDay had not carried out the proper checks to ensure people had consented to receive the emails.
Andy Curry, ICO enforcement group manager, said: “Firms cannot get away with failing to follow the rules designed to protect people from the irritation and, on occasions, distress that nuisance calls, emails and texts cause.”
A spokesperson for the credit card provider said: “NewDay respects the ICO’s decision and deeply regrets the impact that this has had on those potential customers who received these marketing emails.
"We took swift action to close these marketing channels as soon as this matter was brought to our attention and have been working closely with the ICO ever since. We have also been quick to change our marketing policies and review all relationships with third party providers to ensure that this does not happen again.”