Update 10 July

We’ve received a small number of reports from customers over the last 24 hours or so about delayed delivery of emails they are sending. This appears to be mainly limited to messages where the recipient address is at Yahoo or Hotmail/Outlook.

Our team has been investigating the cause of the imposed delay, and we’ve identified a customer email account that has been used to send spam. For the time being the account has been disabled and we are making efforts to contact the customer. It’s most likely that the account had been compromised.

Malicious actors deploy a range of methods to try to gain access to legitimate email (and other) accounts. This might include sending so-called phishing emails, designed to look genuine and draw recipients into providing their account password. This is why it is crucially important that all customers take great care not to share their account details with anyone untrusted.

The National Cyber Security Centre offers a useful set of tips on how to stay safe online.