Comparison site MoneySupermarket has been fined £80,000 after it sent an email to millions of customers who had opted out of marketing messages.
The Information Commissioner's Office (ICO) said today MoneySupermarket broke the law when it sent out the email between 30 November and 10 December last year.
In total it was sent to some 7.1 million customers who'd previously said they did not want to be contacted, giving them the opportunity to opt back in. The ICO said the email was received by almost 6.8 million customers.
The email sent by MoneySupermarket included a section headed 'Preference Centre Update' which read: "We hold an email address for you which means we could be sending you personalised news, products and promotions. You've told us in the past you prefer not to receive these. If you'd like to reconsider, simply click the following link to start receiving our emails."
However, the ICO said asking customers to consent to future marketing messages when they have already opted out is against the law.
ICO head of enforcement Steve Eckersley said: "Organisations can't get around the law by sending direct marketing dressed up as legitimate updates.
"When people opt out of direct marketing, organisations must stop sending it, no questions asked, until such time as the consumer gives their consent. They don't get a chance to persuade people to change their minds.
"Emails sent by companies to consumers under the guise of 'customer service', checking or seeking their consent, is a circumvention of the rules and is unacceptable. We will continue to take action against companies that choose to ignore the rules."
A spokesperson for MoneySupermarket said: "We take the protection of our customers' data and privacy very seriously. We apologise unreservedly to the customers affected by this isolated incident and we have put measures in place to ensure it doesn't happen again."