Connecting London and Amsterdam: The Scylla Subsea Cable System
A high-capacity, unrepeatered subsea cable system engineered to strengthen Western Europe’s most important digital corridor, linking London and Amsterdam with resilient, low-latency connectivity.
Project Overview
Scylla is a next-generation subsea fibre optic cable system connecting the United Kingdom and the Netherlands. Commissioned by euNetworks, it is the first new Subsea cable between the two countries since the early 2000’s and entered service in 2001.
While the landfalls are located at Lowestoft (UK) and IJmuiden (Netherlands), Scylla is strategically designed to serve the major metropolitan hubs of London and Amsterdam, integrating seamlessly with euNetworks’ wider terrestrial network.
The system forms a core part of euNetworks’ long-haul architecture, acting as “Super Highway 2” between London and Amsterdam and interconnecting with Super Highway 1 (Dublin–London–Lowestoft). Together, these routes enable resilient, data-centre-to-data-centre connectivity across Dublin, Manchester, London and Amsterdam, supporting long-term Western European bandwidth demand.
MDM was appointed to deliver the full lifecycle engineering, permitting, installation and ongoing operational support for the Scylla system.
Scylla's Challenge:
Delivering Scylla required overcoming one of Europe’s most demanding subsea environments. The North Sea is characterised by high tidal currents, mobile sand waves, intense fishing and a long history of cable breaks and service disruption.
At the same time, the project had to navigate cross-border regulatory requirements, secure approvals in both the UK and the Netherlands, and identify technically viable landfall locations capable of supporting long-term system resilience.
The challenge was not simply to install a new cable, but to engineer a solution to ensure that the cable would remain buried in the seabed over the lifetime of the system, despite the highly mobile sand wave environment.
The Solution:
MDM delivered a full life-cycle engineering and project management solution, ensuring Scylla was designed, permitted, installed and validated with confidence. Our approach combined advanced route engineering, innovative installation techniques and close stakeholder coordination from early feasibility through to live operation.
MDM’s end-to-end subsea engineering capability and deep regional experience were central to delivering Scylla, reflecting the specialist services we provide across the full subsea cable lifecycle.
Project Management & Delivery Oversight
MDM provided full project management for the complex subsea cable installation, maintaining oversight across engineering, permitting, installation planning and execution to ensure programme certainty and risk control.
Permitting & Stakeholder Management
Working in partnership with TAUW, a European Environmental Engineering Consultancy, we managed permitting and stakeholder engagement in both the UK and the Netherlands, coordinating with regulators, marine authorities and other stakeholders to secure approvals for a cross-border system operating in a highly regulated marine environment.
Site Development & Landfall Engineering
MDM supported the identification and development of optimal landing locations, including an innovative Horizontal Directional Drilling (HDD) solution at the IJmuiden landfall, minimising environmental impact while ensuring long-term stability.
Engineering, Installation & Technical Oversight
MDM delivered the system design, installation planning and construction administration, integrating survey data, seabed modelling and route optimisation to support a safe and technically robust installation.
Key Features of the SCYLLA System
Designed to support modern cloud, AI and data-centre traffic, Scylla incorporates several technical advantages, including:
unrepeatered system
A 211 km subsea cable connecting the UK and the Netherlands without offshore repeaters, simplifying system architecture and improving long-term reliability.
High
fibre pair count
A high-capacity optical design engineered to support long-term growth in cloud, AI and data-centre traffic across Western Europe.
Ultra-low loss fibre technology
Built using Corning SMF28® ULL G654.C pure silica fibre, enabling exceptional attenuation performance and long unrepeatered spans.
Deep, secure burial
Installed using a jetted micro-routing approach and the CAPJET trenching system, achieving 2–3 metres burial depth, significantly exceeding traditional methods.
Innovative North Sea installation method
The only subsea cable in the North Sea installed using a jetted micro-routing burial technique, reducing exposure to fishing activity and historic cable strike zones.
The MDM Results
Scylla delivers a secure, diverse and future-ready connection between the UK and mainland Europe, strengthening one of the region’s most important digital corridors.
Network Integration:
Successfully connected euNetworks' Super Highway infrastructure, creating seamless data centre-to-data centre connectivity across Dublin, Manchester, London, and Amsterdam
Future-Proof Architecture:
Unrepeatered design enables technology upgrades through endpoint equipment replacement only—no underwater intervention required—significantly reducing lifecycle costs while maximizing infrastructure longevity
Regional Leadership:
Project success positioned MDM as preferred partner for complex North Sea subsea installations
Two years after deployment, a post-installation burial survey confirmed that predicted sand-wave movement has further increased Scylla’s burial depth beyond the original 2–3 metres, validating MDM’s innovative engineering approach.
MDM continues to support Scylla through ongoing Operations & Maintenance on behalf of euNetworks, ensuring long-term system performance and continuity throughout the asset’s lifecycle.
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