Tobias Ellwood told Sky News there was a "1939 feel to the world" and that Britain was not equipped to deal with "what is coming over the horizon".

He was responding to a report in The Daily Telegraph, which said that later on Wednesday, General Sir Patrick Sanders was due to give a speech warning the British public would have to be called up to fight if the UK goes to war because the military is too small.

Politics Live: Tory infighting breaks out after PM faces call to quit

Mr Ellwood, who has served alongside General Sir Patrick, said he was "one of the most cerebral thinkers that we've got" and a "strategist".

"We need to listen and listen carefully, we've been too complacent," Mr Ellwood said.

"What's coming over the horizon should shock us. It should worry us and we are not prepared."

The MP for Bournemouth East said that following decades of post-Cold War peace there was a growing sense authoritarian states could "exploit our timidity, perhaps our reluctance to really put fires out" - pointing to Russia's invasion of Ukraine.

"So Patrick Sanders is saying prepare for what's coming over the horizon - there is a 1939 feel to the world right now," he said. "These authoritarian states are rearming.

"There's a risk averseness about the West in wanting to deal with that and our global institutions such as the United Nations aren't able to hold these errant nations to account."

According to The Daily Telegraph, General Sir Patrick would not support conscription but wants the government to "mobilise the nation" in the event of war with Russia.

Read More:
Minister rejects claims army will shrink after danger warning
Critical' for NATO allies to grow defence budgets

He has previously been outspoken about the need to rebuild the UK's warfighting capability in the wake of Vladimir Putin's attack on Ukraine, saying Britain's combat power has been hollowed out by consecutive governments since the end of the Cold War.

The Ministry of Defence declined to comment, but earlier this week, Defence Secretary Grant Shapps denied the size of the army was "shrinking" and said under the Conservatives, it would not dip below the current level of around 73,000.

However, Mr Ellwood said he agreed with General Sir Patrick that the army is "overstretched", in part because of issues to do with pay and accommodation.

He said the army, as well as the navy, is about "half the size of what it should be" while the RAF is lacking the equipment it needs.

"In the Cold War, we had 36 fast jet squadrons, we're down to about six today. And that's just an illustration of just how small our armed forces are," he said.

The senior MP said the defence budget needed to be upped from its current level of 2% of GDP to at least 3%.

The government's target is 2.5%, but Mr Shapps told Sky News on Sunday that "we're not there yet".

Mr Ellwood said that during the Cold War, defence spending "was about 4%".

He added: "Our world is no longer at peace. We're moving to a world at war. Britain absolutely has a role to play, but we need to upgrade our defence posture."