Construction of the Fehmarnbelt tunnel, the submerged road and rail link designed to connect Germany and Denmark beneath the Baltic Sea, has been disrupted by a cyber incident at the contractor consortium building it, Femern Link Contractors (FLC). The project’s own Danish company, Femern A/S, confirmed the disruption on Tuesday, 13 October, while the state body supervising the scheme offered only a brief acknowledgement that its contractor had reported a technology problem.
- Confirmed: Femern A/S has verified a cyber incident at FLC, the consortium responsible for the tunnel’s concrete elements and its immersed section.
- Operational fallout: Access cards stopped working, staff were asked to stay off computers and Wi-Fi, and work barges were left idle near Rødbyhavn on the Danish island of Lolland.
- Unresolved: No actor has been identified, and there is no confirmation of stolen data, a ransomware demand or any officially announced investigation.
A terse confirmation and the clues from the site
Jens Villemoes, communications director at Sund & Bælt, the Danish state company that oversees the project, said FLC had informed his organisation about the incident, that the two sides remain in contact and that no further information was available. That is the full extent of the official record so far.
FLC reported the incident to Sund & Bælt, both parties are in contact, and there was nothing more to add, according to the account given by Jens Villemoes, the company’s communications director.
The granular detail has come from local Danish press reporting rather than from the project’s own channels. Those accounts place the start of the trouble on Monday, 12 October, when access cards stopped functioning, workers were instructed not to use computers or Wi-Fi, and several work vessels halted in the Rødbyhavn area. Femern A/S has not confirmed those individual incidents one by one, so they are best treated as reported operational symptoms rather than fully verified facts.
Equally absent is any confirmation that data was stolen, that the incident involved ransomware, or that a formal investigation has been opened. The tunnel’s backers have not named a suspected attacker.
Why a tunnel cyberattack matters beyond the Baltic
The target is the main contractor on one of Europe’s largest civil engineering works, and the timing is poor. FLC manufactures the tunnel’s giant concrete elements and constructs both the immersed section and the landside portals. The consortium includes Vinci Construction Grands Projets of France, Denmark’s Per Aarsleff, and the German firms Wayss & Freytag and Max Bögl, alongside Belgian and Dutch partners.
The numbers behind the project explain the stakes. The crossing will run 18 kilometres and is assembled from 89 prefabricated elements, 79 of which measure 217 metres in length. The fourth element was immersed on 28 September, taking the placed total to almost 900 metres. The schedule was already carrying a delay of roughly two years, announced in May, against an opening originally envisaged for 2029.
Once operational, trains are expected to cross in around seven minutes and cars in about ten, cutting the rail journey between Hamburg and Copenhagen to roughly two and a half hours. The completed structure is set to rank as the world’s longest road and rail tunnel.
The wider pattern is what makes this incident notable. Attacks of this kind increasingly aim at physical operations rather than data alone, and a construction site full of barges, cranes and digital access controls is critical infrastructure in its own right. When a project is already running behind schedule, even a short interruption to access systems and computing carries scheduling consequences. The key unknown is how many days, or weeks, this adds to a timeline that had little slack left to give.
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