Betting fans have been warned they may be the victims of a hacking breach. Customers of Betfair and Paddy Power have been told that the company has suffered a data breach, with as many as 800,000 customers in Britain and Ireland impacted. The betting sites “recently detected that an unauthorised third party” gained access to “limited betting account information” relating to some of its customers, the company said in an email to customers. Paddy Power and Betfair are owned by Dublin-based Flutter Entertainment, which has 4.2 million average monthly users across its four betting brands in Ireland and Britain, generating $3.6 billion (€3.07 billion) in revenue, according to its annual report. It is the world’s biggest publicly listed betting company, with a market capitalisation of $50.6 billion. It is understood that the breach, which affected nearly one in five monthly customers, was detected within the last four weeks, and the company say they have done all they can to secure the site, as well as notifying the Data Protection Commission (DPC) in Ireland and the UK’s Information Commissioner’s Office. “The nature of this incident means that regrettably some of your personal information has been impacted,” the firm said in an email to customers. Here is all we know about the breach: The company have said usernames, email addresses and IP addresses were all leaked in the breach. There was also a limited number of incidents in which limited address details were accessible. An email to Betfair customers said the breach impacted “details of some recent activity on your account and technical data like your device ID and IP address”, but it is not thought any banking details were accessed, with a spokesman confirming: “No passwords, ID documents or usable card or payment details were impacted.” The company confirmed that a “full investigation” has since been carried out to ascertain just how the breach happened and the level of information that was accessed. They said they have hired external IT security experts to look into the incident, and it said it would examine the cause of the breach and how they could prevent it happening again, by increasing the security of its network and customer data. The company said it believes “the unauthorised access has been removed and the incident contained” and that the investigation concluded that the “affected information was isolated to limited betting account information”. All customers who had their information accessed in the breach should have been contacted by email by now, the company have said. But anyone who has questions can access the customer services team via the help icon in their app or online account.