In a busy week for the UK Information Commissioner’s Office, Marriott has said the organisation plans to issue it with a £99 million fine following a data breach.

The decision relates to a breach in the Starwood guest reservation database which potentially comprised data from hundreds of millions of guests.

As many as 393 million people may have been impacted by the breach.

Of those affected, around 30 million were residents of 31 countries in the European Economic Area.

Seven million were UK residents.

It is believed the vulnerability began when the systems of the Starwood hotels group were compromised in 2014.

Marriott subsequently acquired Starwood in 2016, but the exposure of customer information was not discovered until 2018.

The ICO’s investigation found that Marriott failed to undertake sufficient due diligence when it bought Starwood and should also have done more to secure its systems.

Information commissioner, Elizabeth Denham, said: “The GDPR makes it clear that organisations must be accountable for the personal data they hold.

“This can include carrying out proper due diligence when making a corporate acquisition, and putting in place proper accountability measures to assess not only what personal data has been acquired, but also how it is protected.

“Personal data has a real value so organisations have a legal duty to ensure its security, just like they would do with any other asset.

“If that doesn’t happen, we will not hesitate to take strong action when necessary to protect the rights of the public.”

Marriott initially admitted it has been compromised in November last year.

The hotel giant has the right to respond before any final determination is made and a fine can be issued by the ICO. 

“The company intends to respond and vigorously defend its position,” said a statement.

Marriott International president, Arne Sorenson, added:  “We are disappointed with this notice of intent from the ICO, which we will contest. 

“Marriott has been cooperating with the ICO throughout its investigation into the incident, which involved a criminal attack against the Starwood guest reservation database.

“We deeply regret this incident happened. 

“We take the privacy and security of guest information very seriously and continue to work hard to meet the standard of excellence that our guests expect from Marriott.”

The Starwood guest reservation database that was attacked is no longer used for business operations.