Professional legal privilege under pressure?

On behalf of the WODC, Joost Nan, Professor of Criminal (Procedural) Law, Paul Mevis, Professor of Criminal Law, Nina Holvast, Associate Professor of Sociology of Law, and Pieter Verrest, Professor of Criminal (Procedural) Law, all affiliated with Erasmus School of Law, carried out an international comparative legal study into professional legal privilege. The research focused on the Netherlands, Germany, France, Switzerland, and England and Wales. We spoke further with Nan about the report.

Why this research?

Persistent problems in Dutch practice prompted the study. Nan explains: “In practice, there are various issues surrounding the (safeguarding of) professional legal privilege, particularly for lawyers and civil-law notaries. For this reason, the WODC commissioned this research for the Ministry of Justice and Security.”

Although the importance of legal privilege is widely recognised, it is proving increasingly difficult in practice to keep confidential information out of the reach of investigative authorities. This is especially true in the context of digital investigations. Nan elaborates: “Everyone we spoke to, both in the Netherlands and abroad, acknowledges the value of legal privilege. In practice, however, when dealing with large volumes of digital data, it is difficult to prevent privileged material from ending up in the case file accessed by investigators.”

The Netherlands compared with other countries

A key part of the study involved a comparison with other European legal systems. One striking finding is that the Netherlands applies a relatively broad interpretation of legal privilege, combined with extensive procedural safeguards. In other countries, legal privilege is often more narrowly defined and organised more pragmatically. Nan describes the difference as follows: “We have a broad concept of legal privilege, followed by a rather vaguely defined exception. In other countries, legal privilege primarily concerns communication between the client and the professional bound by confidentiality, and exceptions are generally not permitted. That is clearer.”

However, this clarity does not mean that the problem has been solved elsewhere. Determining which data may or may not be used by investigative authorities remains challenging abroad as well. The main difference lies in how this uncertainty is handled. “Abroad, we observed a somewhat more ‘relaxed’ approach, where parties more often try to carry out the filtering themselves. Material that was wrongly not filtered out ultimately could not be used. As a result, there was less frequent recourse to the courts,” Nan explains.

The ‘watertight’ Dutch system

The Netherlands stands out for its ambition to make the filtering process as watertight as possible, with a central role for the investigating judge. While this offers a high level of protection, it also has drawbacks. “It is simply very difficult to filter privileged material from a tangled mass of data, and to do so consistently under the direction of the investigating judge,” says Nan. “That takes time and manpower, and the system does not have unlimited capacity.” As a result, criminal investigations can sometimes be significantly delayed because the process becomes bogged down in practical and organisational difficulties.

Filtering digital data

The study reveals that the filtering of digital data, in particular, constitutes a structural bottleneck. Often, a complete dataset is first seized, after which it is only later assessed which parts fall under legal privilege. This process is technically complex, error-prone and labour-intensive. The report therefore argues for a sharper delineation of legal privilege and a reform of the filtering process. Nan comments: “This would allow quicker assessments of what does and does not fall under legal privilege, and might also make it possible for this to happen more informally than is currently the case.”

Shared responsibility

A key theme in the report is the shared responsibility of authorities and professionals, who are bound by a duty of confidentiality. Not only investigative bodies, but also lawyers and civil-law notaries themselves play a role in protecting confidential communication. “The legal profession and the notarial profession themselves emphasise that they have a responsibility to safeguard the confidentiality of their documents and communications,” Nan explains. By using clearly identifiable and well-defined communication channels whenever possible, it becomes easier to identify where privileged material is located. This can help to separate confidential and non-confidential information, either beforehand or afterwards. At the same time, the researchers acknowledge that this is not always straightforward in practice, partly due to the diversity of clients and forms of communication.

What does this mean for the future?

The study shows that there is no ideal model. Every system struggles with the same fundamental tension: how to protect confidentiality without making criminal fact-finding impossible. Nan summarises the key message of the report for legislators and practitioners as follows: “Keep the system simple and try to encourage parties to carry out the filtering themselves, where necessary under the supervision of a judge, but without requiring that judge to make an all-encompassing decision every time.”