Dentsu UK has confirmed a data security incident affecting files from its Merkle network — potentially exposing sensitive employee information, including bank and payroll details.
What has happened in the Dentsu data breach
The global advertising and marketing group detected “unusual activity” on servers within Merkle’s network, a trading division of Dentsu UK Limited. After discovering the issue, the company activated its incident-response protocols, contained the activity, and launched an internal investigation with help from external cybersecurity specialists.
The Information Commissioner’s Office (ICO), the National Cyber Security Centre (NCSC) and law enforcement have all been notified.
So far, Dentsu says the files accessed may include:
- Bank and payroll details
- Salary information
- National Insurance numbers
- Personal contact details
The review is ongoing, but the incident appears to affect both current and former employees of Dentsu’s UK operations.
The company says it has directly contacted all those whose details may have been compromised and has taken steps to prevent the data from being publicly disclosed. To help protect affected individuals, Dentsu is offering one year of free Experian Identity Plus membership, which includes credit and dark-web monitoring.
What you can do if you’re affected
Payroll and HR breaches can be especially serious, as the data involved often includes both financial and identity information — the kind that can be used for fraud or phishing.
If you worked for Dentsu UK or Merkle in the past and are worried your information could be included, here are some steps to take now:
- Monitor your accounts – Regularly review your bank and credit card statements for any suspicious activity.
- Be alert to scams – Treat unsolicited calls, texts, or emails asking for personal or financial details with caution.
- Report identity fraud – If you suspect your data has been misused, report it to your bank and Action Fraud via actionfraud.police.uk.
You can get more handy tips on how to safe after a data breach here.
We’ll continue to provide more information on the Dentsu data breach, including updates as the investigation develops.
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