When executives hear the words “data breach”, they often imagine hooded hackers, blinking servers and a dramatic cyber-attack straight out of a thriller. Sometimes that does happen. The UK armed forces learned this in 2024 when a major UK armed forces data breach saw personal details of service personnel and applicants accessed by attackers.

However, most breaches affecting employee data are far less glamorous and far more embarrassing. A data breach can be as simple as:

• Sending an HR spreadsheet to the wrong email address
• Losing a laptop or memory stick containing payroll information
• Leaving staff documents in an unlocked shared drive
• Printing sensitive staff data and misplacing it during travel

None of these require a sophisticated criminal mastermind. They require only a moment of carelessness. The consequences can be very serious.

In 2018, Carphone Warehouse was fined £400,000 by the Information Commissioner’s Office (ICO) after failing to secure its systems properly, putting both customer and employee data at risk.

More recently, the ICO issued a formal reprimand to GRS (Roadstone) Limited in 2023 after a threat actor was able to access and extract personal data belonging to current and former employees because appropriate security measures were not in place.

Even government departments are not immune. The Cabinet Office faced an ICO investigation following the 2020 New Year Honours list data breach, where personal details of honours recipients were accidentally disclosed online.

Not every case results in a financial penalty, but they all bring scrutiny, regulatory attention, and reputational damage.

The uncomfortable truth is that many organisations have already experienced employee data breaches without properly recognising them. A spreadsheet with staff addresses sent to the wrong distribution list? That’s a breach. A memory stick containing payroll data misplaced during an office move? Also a breach. In other words, it’s entirely possible that your organisation has already caused a breach of employee data and simply didn’t realise it.

The real issue is what happens next. Do employees know how to report an incident? Does management take it seriously? Is there a clear process for assessing whether the breach must be reported to the ICO?

Leaders who assume breaches only happen to “other companies” are usually the same leaders who discover—far too late—that their own internal processes are held together with sticky tape and hope.

If your organisation hasn’t tested how it handles employee data incidents, now might be a very good time. Preferably before someone leaves a spreadsheet full of staff National Insurance numbers on the train to Manchester.