A UK spy chief has said Russian President Vladimir Putin's "personal war" is failing.
Sir Jeremy Fleming said the war in Ukraine was in "chaos" after he issued his first public statement since it began.
He said new intelligence has shown that Russian soldiers are refusing to carry out orders and sabotaging their own equipment as they grow increasingly frustrated by the conditions in Ukraine.
Sir Jeremy also claimed that troops had accidentally shot down their own aircraft, saying Putin's advisors had been lying to him about Russia's many losses out of fear of what action the leader would take.
According to Sir Jeremy, Putin has been forced to alter his strategies, which has led to "barbarity against civilians and cities".
During a speech in the Australian capital Canberra to celebrate the 75th anniversary of the Australian Signals Directorate, he said: "'We're now seeing Putin trying to follow through on his plan, but it is failing. And his Plan B has been more barbarity against civilians and cities.
"It increasingly looks like Putin has massively misjudged the situation. It's clear he misjudged the resistance of the Ukrainian people.
"He underestimated the strength of the coalition his actions would galvanise. He underplayed the economic consequences of the sanctions regime.
"He overestimated the abilities of his military to secure a rapid victory.'
He added: "We've seen Russian soldiers – short of weapons and morale – refusing to carry out orders, sabotaging their own equipment and even accidentally shooting down their own aircraft.
"Even though we believe Putin's advisers are afraid to tell him the truth, what's going on and the extent of these misjudgments must be crystal clear to the regime."
The head of Britain's eavesdropping intelligence agency said Putin's campaign was now riddled with problems due to his "strategic miscalculation".
He said: "We know Putin's campaign is beset by problems – low morale, logistical failures and high Russian casualty numbers.
"Their command and control is in chaos. We've seen Putin lie to his own people in an attempt to hide military incompetence."
Sir Jeremy added: "It all adds up to the strategic miscalculation that Western leaders warned Putin it would be. It's become his personal war, with the cost being paid by innocent people in Ukraine and increasingly by ordinary Russians too.
"The great irony is that through his actions, Putin has brought upon himself exactly what he was trying to avoid – a Ukraine with a renewed sense of nationhood, a Nato that is more united than ever, and a global coalition of nations that condemn his actions."
His address came amid Western intelligence services claiming that Putin "didn't even know his military was using and losing conscripts... showing a clear breakdown in the flow of accurate information".
A US official said: "We have information that Putin felt misled by the Russian military.
"There is now persistent tension between Putin and the MOD, stemming from Putin's mistrust in MOD leadership."
Russia has lost as many as 15,000 troops as well as more than 2,000 military vehicles.
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