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The Information Commissioner’s Office (ICO) has today issued a warning to organisations to use alternatives to the blind carbon copy (BCC) email function when sending emails containing sensitive personal information, following a catalogue of business blunders.

The warning comes as the ICO publishes new guidance to help organisations understand the law and good practice around protecting personal information when sending bulk emails.

Mihaela Jembei, ICO Director of Regulatory Cyber, said:

“Failure to use BCC correctly in emails is one of the top data breaches reported to us every year – and these breaches can cause real harm, especially where sensitive personal information is involved.

“While BCC can be a useful function, it's not enough on its own to properly protect people's personal information. We’re asking organisations to assess the nature of the information and the potential security risks when deciding on the best method to communicate with staff or customers. If organisations are sending any sensitive personal information electronically, they should use alternatives to BCC, such as bulk email services, mail merge, or secure data transfer services.

“This new guidance is part of our commitment to help organisations get email security right. However, where we see negligent behaviour that puts people at risk of harm, we will not hesitate to use the full suite of enforcement tools available to us.”

The critical importance of using appropriate methods to send bulk communications is emphasised in recent ICO enforcement action. Earlier this month the ICO reprimanded two Northern Irish organisations for disclosing people’s information inappropriately via email. And in March the ICO issued a reprimand to NHS Highland for a “serious breach of trust” after a data breach involving those likely to be accessing HIV services.

According to ICO data, failure to use BCC correctly is consistently within the top 10 non-cyber breaches, with nearly a thousand reported since 2019. The education sector is the biggest offender for BCC breaches, with health in second, then local government, retail and the charity sector rounding out the top five.

Email best practices for organisations

Under data protection law, organisations must have appropriate technical and organisational measures in place to ensure personal information is kept safe and not inappropriately disclosed to others.

Organisations that use and share large amounts of data, including sensitive personal information, should consider using other secure means to send communications, such as bulk email services, so information is not shared with people by mistake.

Organisations should also consider having appropriate policies in place and training for staff in relation to email communications.

For non-sensitive communications, organisations that choose to use BCC should do so carefully to ensure personal email addresses are not shared inappropriately with other customers, clients, or other organisations.

For further advice on email best practices, view our full email and security guidance.

Notes to editors
  1. The Information Commissioner’s Office (ICO) is the UK’s independent regulator for data protection and information rights law, upholding information rights in the public interest, promoting openness by public bodies and data privacy for individuals.
  2. The ICO has specific responsibilitiesset out in the Data Protection Act 2018 (DPA2018), the United Kingdom General Data Protection Regulation (UK GDPR), the Freedom of Information Act 2000 (FOIA), Environmental Information Regulations 2004 (EIR), Privacy and Electronic Communications Regulations 2003 (PECR) and a further five acts and regulations. 
  3. The ICO can take action to address and change the behaviour of organisations and individuals that collect, use and keep personal information. This includes criminal prosecution, non-criminal enforcement and audit. 
  4. To report a concern to the ICO telephone our helpline 0303 123 1113 or go to