UK ambulance services have been targeted by Russian hackers, risking disruption to their communication systems, with the potential to severely hamper Britain’s emergency services.

Intelligence material seen by i shows that over the past 12 months, a Kremlin-protected hacking network has targeted key suppliers to the UK Ambulance Services and Ministry of Defence (MoD).

This week, MI5 director Ken McCallum announced that Russia is on a “sustained mission” to create “mayhem” across Britain and Europe.

i gained rare exclusive access to a large database of previously stolen information used by hackers to identify and target a key supplier to the Ambulance Radio Programme (ARP), which connects ambulances to the NHS and other emergency responders.

The hackers, according to intelligence seen by i, were able to access email threads discussing the ARP, and details of key personnel and components involved in its security, exposing some of the inner workings of UK Ambulance Services’ secure communication systems.

The extracted information significantly increases the risk of further attacks on the ARP which could crash the system. This would have the potential to leave ambulance command centres unable to communicate with drivers and the police or fire services, or prevent them from receiving vital information about the precise location of major incidents, four UK intelligence sources told i…