On Thursday, Britain unveiled plans to impose prison terms reaching 14 years and unlimited financial penalties for those who damage undersea cables and pipelines. The move reflects mounting alarm about the exposure of subsea infrastructure to what governments term "hybrid warfare"—a combination of physical destruction and digital assault targeting both the cables themselves and associated onshore facilities.

The white paper accompanying the consultation identifies the scope of what the legislation would protect: telecommunications cables, electricity interconnectors and pipelines that carry 99% of the U.K.'s international data traffic and supply 74% of its gas.

The proposed framework would supersede the Submarine Telegraph Act 1885, a law from the Victorian period that imposes only a maximum £1,000 fine—far below actual repair expenses—and up to five years' imprisonment for intentional damage.

The Estlink 2 electricity cable linking Finland and Estonia, severed by the anchor of the Eagle S oil tanker on Christmas Day 2024, illustrates the scale of potential costs. Grid operator Elering put restoration expenses at between €50 million and €60 million ($56 million to $67 million). Proceedings against senior officers of the vessel remain underway.

Tiered penalties and new safeguards

The new legislation would establish graduated penalties depending on culpability. Those convicted of deliberate damage would face up to 14 years imprisonment, those responsible for reckless damage up to 10 years, and those guilty of gross negligence up to two years.

Beyond criminal sanctions, the government intends to impose statutory security and resilience obligations on subsea telecommunications operators, with authority to instruct cable and repair companies based on national security considerations. Fiber-optic sensing systems, which can monitor maritime activity but risk disclosing classified data, would be subject to separate regulations.

Telecoms minister Ian Murray and energy minister Michael Shanks stated in a joint introduction that "the risks to critical subsea infrastructure was involving," referencing an earlier 2024 warning that a Royal Navy attack submarine had surfaced near a Russian spy vessel engaged in mapping this infrastructure in British territorial waters.

Matt Western, chair of Parliament's Joint Committee on the National Security Strategy, endorsed the initiative, remarking that "the legislation covering attacks on undersea cables was written in a different age and it is right that a White Paper has been brought forward to bring it up to date."

Distinguishing accident from intent

Determining whether cable incidents are accidental or deliberate remains a significant challenge for enforcement. Jurisdictional complications have hindered prosecutions in other cases, and disagreement persists over whether particular incidents represent careless accidents or calculated Russian efforts to destabilise European infrastructure.

When the Estlink 2 cable was damaged, Finnish investigators initially suspected intentional sabotage. However, officials from multiple North Sea and Baltic nations later told Recorded Future News that they increasingly viewed this and other Baltic Sea cable breaks as unintentional, citing investigation findings, intelligence assessments and shipping records.

Britain maintains that its cable infrastructure demonstrates strong resilience overall, with most failures stemming from anchors, fishing equipment, natural phenomena or equipment malfunctions. Nevertheless, officials warn of escalating suspicious activity in the region.

In April, the Ministry of Defence reported that British and allied military forces had detected a Russian attack submarine and vessels connected to Russia's Main Directorate of Deep Sea Research, or GUGI, operating near cables and pipelines north of Britain, purportedly surveying such installations for potential wartime destruction.

The 12-week public consultation period runs until January 14, 2027.