BT Group has completed the UK's first quantum-secured communications network linking financial institutions in London and Edinburgh, marking a significant step toward protecting critical infrastructure from future quantum computing threats.

The 650-kilometre fibre link uses Quantum Key Distribution (QKD) technology to create encryption keys that are theoretically impossible to intercept without detection. Six major banks and two insurance firms have already signed up as initial users.

"Quantum computers will eventually break today's encryption standards," said BT's chief technology officer. "This network ensures that Britain's financial system is protected against that threat before it materialises."

The project received £30 million in government funding through the National Quantum Strategy. Experts suggest the technology could be extended to protect government communications and NHS patient data within three years.