In a major development for quantum communications, researchers in the UK have successfully conducted the nation’s first long-distance, ultra-secure data transfer using a quantum network.
This pioneering achievement marks a new chapter in cybersecurity and data transmission, establishing the UK as a leader in the race toward building a large-scale quantum internet.
Engineered by experts from the Universities of Bristol and Cambridge, this sophisticated quantum communications network spans over 410 kilometres of standard fibreoptic cable, linking the two cities through a backbone of cutting-edge quantum and classical technologies.
Dr Rui Wang, Lecturer for Future Optical Networks in the Smart Internet Lab’s High Performance Network Research Group at the University of Bristol, commented: “This is a crucial step toward building a quantum-secured future for our communities and society.
“More importantly, it lays the foundation for a large-scale quantum internet – connecting quantum nodes and devices through entanglement and teleportation on a global scale.”
The power of quantum key distribution and entanglement
At the heart of this achievement lies the integration of two advanced quantum key distribution (QKD) techniques.
The first involves encoding encryption keys in particles of light, making them virtually immune to eavesdropping.
The second leverages quantum entanglement – a phenomenon where particles remain interconnected regardless of distance – allowing data to be secured in ways classical systems cannot replicate.
By combining these QKD approaches, the research team has achieved a robust system capable of maintaining ultra-secure data transmission over long distances.
This is the first time a network of this scale has successfully incorporated both entanglement distribution and quantum-secure key exchange within standard fibre infrastructure.
Demonstrating the network’s capabilities
To showcase the capabilities of the quantum communications network, the researchers carried out several high-stakes demonstrations.
These included a live quantum-secure video call between Bristol and Cambridge, the encrypted transfer of sensitive medical records, and secure remote access to a distributed data centre.
These real-world applications highlight the enormous potential of quantum communications for enhancing digital privacy and protection across sectors such as healthcare, finance, and government.
The results were presented at the 2025 Optical Fiber Communications Conference (OFC) in San Francisco – one of the most prestigious events in the telecommunications industry.
Setting the UK apart in the global quantum race
While other countries have made strides in quantum communications – China’s network now spans over 4,600 kilometres, and Madrid has implemented a multi-node QKD system – the UK’s recent accomplishment sets it apart.
Unlike previous trials, this network simultaneously supports entanglement distribution and conventional QKD while integrating seamlessly with classical data infrastructure.
Previous milestones in the UK include Cambridge and Toshiba’s metro-scale network with record-breaking key rates and Bristol’s entanglement-sharing network.
However, this new breakthrough consolidates multiple quantum-secure technologies into a single, cohesive system on a national scale, something no other project has achieved so far.
Built on a decade of innovation
This success builds on years of work through the UK Quantum Network (UKQN), supported by the Engineering and Physical Sciences Research Council (EPSRC) and developed as part of the Quantum Communications Hub.
The current infrastructure connects two metropolitan networks in Bristol and Cambridge through four long-distance optical fibre links and three intermediate nodes, utilising the EPSRC’s National Dark Fibre Facility for dedicated research.
The network’s reconfigurable architecture, made possible by low-loss optical switches and single-mode fibre, supports both classical and quantum traffic. This makes it an ideal testbed for scalable quantum communication technologies.
Toward a global quantum internet
Looking forward, the research team plans to expand their efforts under a newly funded EPSRC initiative: the Integrated Quantum Networks Hub.
The project aims to establish scalable quantum networks that connect everything from local quantum processors to national and even intercontinental communication systems via low-Earth orbit satellites.
This next phase could usher in a new era of global connectivity, where information is shared securely through quantum entanglement and teleportation, bringing the vision of a quantum-secured internet closer to reality.
