Mayfair Jeweller 77 Diamonds Hit by Massive Cyberattack

By the Editorial Team · Sunday, September 6, 2026

London-based jeweller 77 Diamonds has suffered a cyberattack in which hackers claim to have stolen personal and purchase data belonging to over 400,000 customers, with the information reportedly being auctioned on the dark web. The company is investigating the breach, notifying affected customers, and working with cybersecurity experts and authorities to mitigate potential risks amid a broader rise in cybercrime targeting UK businesses.

London-based jeweller 77 Diamonds has become the target of a significant cyberattack, with hackers claiming to have accessed and stolen customer data, including hundreds of thousands of addresses. The company, known for its bespoke engagement and wedding rings, counts several high-profile clients among its customers, including singer and TV presenter Myleene Klass and Premier League footballers. The Metropolitan Police cyber crime unit is currently investigating the breach.

The hackers allege they have obtained data on more than 409,000 customers, which reportedly includes names, email addresses, postal addresses, and purchase records detailing the value and billing information for rings. This information is reportedly being offered for auction on the dark web. 77 Diamonds has emphasized that it does not store customers’ banking details.

Tobias Kormind, managing director of 77 Diamonds, informed customers via email that the company is investigating unauthorized access to its customer database and has taken immediate action to secure its systems. Cybersecurity experts have been engaged to assist in the investigation, and the Information Commissioner’s Office has been notified. Kormind stated that while it cannot be confirmed which specific information was accessed, the company is contacting affected customers to enable them to take necessary precautions. No reports of customers being targeted as a result of the breach have been received to date.

Founded with a focus on custom-designed rings, 77 Diamonds produces about ten pieces daily, ranging in price from a few thousand pounds to over £1 million depending on complexity. The firm employs 150 staff and operates 14 branches across the UK, Europe, and the Middle East. Its 2024 financial accounts show a turnover of £33 million. Kormind invested £300,000 into the business in 2005 through remortgaging his London flat.

One customer who purchased a customized diamond ring in 2015 expressed concern about the possibility of her personal details being in the hands of criminals but noted greater worry for those who had bought rings more recently. The company has urged customers to remain vigilant against unsolicited emails, texts, or phone calls that may fraudulently claim to be from 77 Diamonds.

This incident occurs amid a wider increase in cyberattacks targeting UK businesses. A recent government survey found that 43 percent of businesses experienced cyberattacks in the previous year. The annual economic cost of cybercrime to the UK is estimated at £14.7 billion. Authorities continue to stress the importance of cybersecurity measures in protecting consumer data.

This article was reported by synthesizing coverage from multiple independent news outlets to present a balanced, unbiased account. Read about our editorial standards. Spotted an error? Let us know.