If the current level of cyber attacks on defence were an air war, it would be the Blitz, the UK's head of Strategic Command has said.
General Sir Patrick Sanders made the comments during a visit to Exercise Army Cyber Spartan IV at Blandford Camp in Dorset.
The exercise aimed to test the ability of soldiers to repel and prevent cyber attacks – increasingly important in an era of computer reliance.
Millions of network and cyber events affect UK defence, including about 60 each day which require intervention.
The Government recently announced that reservists can be called into permanent service to support 'CEMA' (Cyber and Electromagnetic Activities) for the first time.
Two hundred and fifty British defence personnel, along with teams from Europe, have been competing in the exercise, as the Army also hopes to talent spot for its new specialist cyber force.
During the five-day contest, the red team – the enemy – moved around the network, simulating attacks from real-world actors, including organised crime, nation states and terrorists.
Major Phil Jones, Officer Commanding 31 Signal Squadron, told Forces News: "What we're trying to do is put as much complexity and engineering challenge into the environment so that we can get the maximum possible learning from them.
"So that includes not just the traditional office network-based email, files, servers, Microsoft Teams, Sharepoint, all the things that people are really familiar with, but it also includes a whole range of actual real-world activity."
This involves remotely piloted vehicles, complete with GPS, camera systems and targeting software, all vulnerable to attack.
There is also an industrial control system which runs the domestic utilities for a fictitious town.
Twenty-four machines, one for each team, represented a communications satellite in space.
Major Jones added: "Yes, the bad guys can turn the solar panels away from the sun, so the power drops, it no longer functions. They can turn the camera away, so the commander no longer has eyes on from that asset.
"Again, it is, to an extent, unrealistic, but no more unrealistic than any other form of military training."
Lieutenant Phil Smith, Royal Dragoon Guards, said: "It's certainly been a big learning curve.
"Some people have been interested in this as a hobby before, some people have only been introduced to it this week."
The winning team goes to Estonia next year to take part in NATO's Exercise Locked Shields.
With millions being invested in the UK's cyber capability, the exercise is part of the growing ambition to make Britain one of the world's foremost cyber powers.