In an exclusive interview, Tobias Ellwood, Defence Select Committee chair, told GB News a Russian invasion of Ukraine is "imminent" and the West has "run out of road" to prevent Putin ordering his troops to attack.
The Bournemouth East MP, who served in Bosnia, says there are "100,000 troops ready to cross the starting line".
A Russian army service member carries a mortar shell during drills at the Kuzminsky range in the southern Rostov region, Russia.
SERGEY PIVOVAROV
Western powers have held numerous rounds of talks with Russian officials in Geneva, Vienna and Brussels but they "have concluded without result", said Ellwood.
Conservative chair of the Defence Committee Tobias Ellwood told GB News Putin may try and "take over" all of Ukraine.
House of Commons
Following the evacuation of some staff from the British embassy in Kyiv, GB News asked Mr Ellwood whether people should be concerned that there will be British casualties in Russia invades Ukraine.
Mr Ellwood said soberly: "Only Putin knows that.
"Putin sent an ultimatum demanding NATO retreat, that of course could never be accepted, but he’s now able to paint NATO as the aggressor.
"...Putin has essentially boxed himself into a corner."
He went on: "A success for him could be anything from taking over the east of Ukraine, the Dontesk area, that is already run by proxies - that’s the low-lying fruit.
"Second option would be moving up to the Dnieper River, the main arterial river, that cuts the country in half.
"The third one, which would be very bold indeed, would be to try and take over the entire country."
Russian T-72B3 main battle tanks during combat exercises at the Kadamovsky range in the southern Rostov region, Russia.
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He added: "But of course once you do that, you own it.
"The further west you go the most western leaning the Ukrainians are."
In response to the escalating threat posed by Russia towards Ukraine, NATO are providing additional military hardware to try and help thwart any potential invading troops.
"NATO will continue to take all necessary measures to protect and defend all Allies, including by reinforcing the eastern part of the Alliance.
"We will always respond to any deterioration of our security environment, including through strengthening our collective defence," NATO Secretary General Jens Stoltenberg said in a statement.
The Defence Committee chair welcomed the response of the NATO alliance:
"It’s absolutely right, although it’s late in the day, that we start to provide weapon systems to Ukraine to help them hold back any Russian advance as best we can.