Wallace, himself a former army officer, said in a speech that Putin's bemedalled generals should face court martial for their handling of the war in Ukraine.

He spoke after Putin defended Russia's offensive in Ukraine in an address to ranks of troops on Red Square for the May 9 holiday celebrating Soviet victory in World War II.

Wallace said in an address at the National Army Museum in London that "through the invasion of Ukraine, Putin, his inner circle, his generals, are now mirroring fascism and tyranny 77 years ago".

He accused them of "repeating the errors of the last century's totalitarian regimes".

"For them, and for Putin, there can be no Victory Day, only dishonour and surely defeat in Ukraine," he added.

Putin has justified Russia's military actions by saying they are carrying out "denazification" of the neighbouring country.

In a speech to troops on Monday, Putin said they were "fighting for the 'Motherland'" in Ukraine, due to an "unacceptable threat", so "no one forgets the lessons of the Second World War".

Wallace said he wanted to "call out the absurdity of Russian generals resplendent in their manicured parade uniforms, weighed down by the gold braid and glistening medals".

"Their top brass have failed their own rank-and-file to the extent that they should face court martial," he said.

He called the military "utterly complicit in Putin's hijacking of their forebears' proud history of... repelling fascism".

Ukrainian President Volodymyr Zelensky on Monday spoke of his pride in Ukrainians who fought to defeat Nazism, saying he would not allow victory in World War II to be "appropriated" by Russians.

Wallace said the reality in Ukraine was that Putin's forces are running out of Russia's most sophisticated precision weaponry "fairly quickly", while relying on Western-made components.

"The truth is that Russia's General Staff are failing, and they know it," he said.

He insisted "Putin must fail in Ukraine" and there was "still potential" for this to happen, while saying it should be up to Kyiv to define what it would accept as victory.