A former head of Joint Forces Command believes Ukraine has the "will to win" and "what it needs from the West is money".
General Sir Richard Barrons told Forces News that Ukraine would require "about $6bn a month to pay for the economy and about $30-40bn a year in military aid".
He highlighted that it was "quite a big bill", but added that "it's much, much cheaper than a war between NATO and Russia".
What the West must do
The retired general said: "The West has to provide money, weapons and ammunition. No longer from the shelves of our Armed Forces in the West but by mobilising industry, that will take some time and there will be a cost to it.
"And providing training and providing humanitarian support to the 17 million Ukrainians who have been displaced.
"And continuing to bear down on Russia strategically, through sanctions and now, I think, deepening sanctions".
He added, that the West must make it "absolutely clear to Russia, that when they lose on the battlefield next year, which is what we are all trying to do, that any thought that they can try and reverse that defeat by resorting to small nuclear weapons or chemical weapons would be a catastrophic mistake for Russia, so don't do it".
NATO's "longer-term game"
The military threat "will come back", Sir Richard said.
"When Russia loses in Ukraine, and it will, and reforms its military and remains bitter and angry if that's the path that Russia chooses to take, then NATO will have to aim off for a steeper Russian military threat in the years to come, and that's why the alliance is playing a longer-term game."
Watch: Ukraine will have to take the fight to the Russians if they are to win, urban warfare expert says.
Urban warfare expert John Spencer told Forces News that the Ukrainians need to use a mix of integrated attack strategies in order to capitalise on Russian weaknesses.
Mr Spencer praised recent Ukrainian advances, saying "many people have learned what others have known... the Ukrainian military is a well-trained, motivated, well-equipped, adaptable, flexible military that planned, prepared and executed a textbook military advance".
He did highlight that the Ukrainians will have to take the fight to the Russians if they are to win the war.