UK citizens have been warned that they could be called up to fight if the war breaks out in Russia.
It comes as Nato bosses have warned allied nations to be prepared to take any actions necessary to fight Vladimir Putin's forces.
General Sir Patrick Sanders, Chief of the General Staff, is set to stress the need for ministers to "mobilise the nation" in the event of a wider conflict against Russia amid its invasion of Ukraine.
Sanders added that the military is "too small" to handle the conflict on its own.
Major General Chip Chapman said the forces need to be fully manned
GBNews
Speaking to GB News Major General Chip Chapman warned that the UK needs to "make sure that the armed forces we have are fully manned".
He said: "Having the conscription debate, it's designed to generate discussion and perhaps new and better ideas In terms of the character of war.
"The person I look to for this is Mark Miley, who's just the outgoing chairman of the Joint Chiefs of Staff in America in 2017. He talked about 5 myths of the army that we need to let go of.
"The first one is that wars might be short, they might not be. And of course that preceded the invasion of Ukraine. The second one is that armies fight wars, but they don't. Nations fight wars. The third one is that armies are easy to create.They aren't.
People could have to go fight for the country
PA"The forth one. You can win wars from afar just by dropping an ordinance. You can't. You need boots on the ground eventually and that requires something between mass."
He explained: "So really there are two concepts I think that have been missing for most defence reviews. The first one is regeneration, How we make sure that the armed forces we have are fully manned, fully stocked, available, and sustainable.
"The second one, which again is designed to sort of generate discussion, is reconstitution. How do you expand both your armed forces and the industrial base to support the type of war that he's reflecting upon?"
"There's been a lot of discussion of course about Gen. Z, the disconnected generation, which has an 8-second filter.
"If it's not interested in something, it moves on and they're the generation more likely to suffer stress and burnout. They're easily offended and they lack motivation and productivity.
Major General Chip Chapman spoke to GBNews
GBNews
"One of the things that is missing is if we deemed or people deemed that it was vital interest, then I'm sure people would sign up.
"But we've been pretty bad at defining what are the vital interests, the major interests, the minor interests of the UK. For example, I would argue that one of the vital interests is of course the free flow of trade.
"This is why the sort of Red Sea Babel Mandev and the Houthi action is key to us.
"Because that increases inflation, disrupts trades around the world and makes life really disastrous for all. And we're just not good at doing that."