Britain's military has engaged in a massive cyber-strike war game scenario which envisioned an attack on Russia's power grid which would black out all of Moscow.

The non-conventional military exercise comes as British defense officials have expressed increasing concern that the UK would be outgunned if under attack by Russia.

An alarming new report in the Sunday Times begins as follows:

Defence chiefs have war-gamed a massive cyber-strike to black out Moscow if Vladimir Putin launches a military attack on the West, after concluding that the only other way of hitting back would be to use nuclear weapons.

Senior security sources have told The Sunday Times they are concerned that Britain has a capability gap that has left commanders with too few weapons to meet Kremlin aggression short of firing a Trident nuclear missile.

Britain's military is said to be exploring a host of alternative measures and "more options" that could constitute a significant blow to Russia's defenses short of launching nuclear war. The Sunday Times continues:

Planning exercises on the threat posed by Russia have left officials "ashen-faced" at the speed with which confrontation with Moscow could escalate.

Whitehall officials have vowed to step up offensive cyber-capability, including the ability to "turn out the lights" in the Kremlin.

Apparently the non-conventional and cyber-weapons strike readiness are part of growing growing tit-for-tat actions and tensions after UK and US officials have accused the Kremlin of aggressive actions ranging from cyberattacks on Western targets to election interference, to the poising of a former spy on British soil.

But officials are concerned that they don't have enough in the UK military arsenal for an adequate response that would halt and deter Russian aggression. One senior military source told The Sunday Times: "If they sank our aircraft carrier with a nuclear-tipped torpedo, what is our response? There's nothing between sinking their submarine and dropping a nuclear weapon on northern Kamchatka."

The source explained further: "This is why cyber is so important; you can go on the offensive and turn off the lights in Moscow to tell them that they are not doing the right things."