Hotel data hack hits up to 500 million guests

How can I tell if I'm affected?

Marriott says it will begin sending emails to affected customers who are on the email database on a rolling basis from today (30 November).

If you're concerned, you can also go to its dedicated help website or phone the UK help centre on 0808 189 1065.

Marriott says it will be offering affected customers a free one-year enrolment to WebWatcher, a service which monitors internet sites where personal information is shared, and alerts customers if their information is found.

You can also take the following steps to minimise the risk of being hit by fraud (see our 30+ Ways to Stop Scams guide for full help):

• Check your bank or credit card transactions regularly. If you spot any unfamiliar or unusual activity, make sure you contact your bank immediately and let it know.
  
  
• If worried, demand a new card. Banks and credit card firms often take different approaches, but if yours isn't routinely replacing cards affected by this breach, you can ask for a replacement card anyway.
  
  
• Beware of 'phishing scams'. Criminals may attempt to use the news of the data breach as an opportunity to trick people affected into revealing information. Remember that no bank or any other genuine organisation will contact you out of the blue to ask for details such as your PIN or banking password, and beware of clicking on any links in text messages or emails.
  
  
• Change your login password. And if you use that password elsewhere, make sure you change it there too. It's good practice to use different passwords – see our Password Security guide for more help.
  
  
• See if your card provider lets you get payment notifications. Some card providers, such as American Express, allow you to get notifications on your phone or tablet every time a payment is made on your card. This way, you can see instantly when a payment goes out if it's one you aren't expecting.