People have taken to Twitter to question how Klarna got hold of personal email addresses.

One wrote: “A number of people (including myself) have received a promo email from Klarna, despite never having used the service..no explanation as to where they got the data from. My guess is retailers are passing on data which surely is not ethical or GDPR compliant?”

Another posted: “Yup just got this too – have never used their services. @Klarna you need to explain [how] you got my data.”

And another wrote: “Hi – I just received a promotional email from you and I don’t know how or why. Can I please have an email address to contact someone to request deletion of my details from your system?”

In response, the buy now pay later shopping site apologised to those who received the newsletter by mistake adding “this was a human error and the email was incorrectly sent for which we are extremely sorry”.

Klarna said the email was sent to Klarna consumers who had recently used one of its products or services, including its ‘checkout technology’ which some retailers use to process payments on their website. This means it processes all credit and debit card transactions for these retailers, have a look at the best holiday promotions.

It added that recipients haven’t been added to a marketing database and they won’t receive further newsletters unless people opt in or download the Klarna app.

The blog post added: “We are currently investigating how this happened, and are taking action to ensure nothing like this can happen again in the future.”

The information watchdog has indicated it will make enquiries about this incident.

An ICO spokesperson, said: “Businesses should only contact individuals for electronic marketing purposes where consent has been provided or, in limited circumstances, where they have an existing relationship with a customer.

“Some members of the public have made us aware of an email sent by Klarna and we will be making enquiries.”