"A Veiled Threat Is Still A Threat": Without Prejudice Privilege Lost Due To 'Unambiguous Impropriety' Exception

• Published date: 11 December 2025
• Law Firm: Arthur Cox
• Author: Mr Keith Smith, Zac Van Horn and Sinéad Britchfield

In a recent judgment¹, the High Court granted an application to admit into evidence that the contents of correspondence marked "without prejudice save as to costs" should be admitted into evidence on the basis that the correspondence contained an implicit threat which amounted to an 'unambiguous impropriety'. This is the first recorded judgment of its kind in Ireland. Arthur Cox LLP acted for the successful applicant.

Background

In the proceedings, the plaintiff alleges that the defendant breached a shareholder' agreement, solicited its employees to work for a competing company and misappropriated intellectual property. As a result, it is claimed that the plaintiff's business has effectively lost all of its value, which it quantifies at over '106 million. These claims are being fully defended by the defendant.

After the pleadings in the case had closed, and the discovery phase had just commenced, the plaintiff's solicitors issued a lengthy letter marked "Without Prejudice Save as to Costs" which referenced an ongoing criminal investigation in Switzerland and invited the defendant to make a proposal to "deal with" both the civil proceedings in Ireland and the Swiss criminal proceedings (the "WP Letter").

The defendant took the view that the WP Letter contained an improper threat against him, particularly as the plaintiff itself...