The Ministry of Defence's National Cyber Force has successfully neutralised a sophisticated cyber attack targeting Britain's water treatment infrastructure, The British Wire can reveal.

The attack, attributed by intelligence sources to a state-sponsored group with links to a hostile foreign power, attempted to compromise the operational technology systems controlling water purification processes at several treatment plants across the Midlands and South East.

"This was not a ransomware attack or a data theft," said a senior defence official, speaking on condition of anonymity. "This was an attempt to interfere with the physical processes that ensure clean water reaches millions of people. The intent was disruption, possibly harm."

The National Cyber Force, established in 2020 as a joint venture between GCHQ and the MOD, detected the intrusion within hours and deployed countermeasures that contained the threat before any operational systems were affected. No water supplies were compromised.

The incident has renewed calls for increased investment in the cyber resilience of Britain's critical national infrastructure. A parliamentary committee report published last month warned that water, energy, and transport systems remain "dangerously vulnerable" to state-sponsored cyber attacks, with many operators still relying on legacy systems designed before the modern threat landscape emerged.