Tory MP Jack Lopresti warned that a North Korean military strike on the US territory of Guam would trigger Article 5 of Nato and spark a British military response

A British MP today warned the UK could join a war against North Korea if the dictatorship attacks the American territory of Guam.

Jack Lopresti said Britain would be under an obligation to step in and defend its Nato ally by force if necessary if Kim Jong-un follows through on his threat to launch a missile strike.

And fellow Tory MP Dr Julian Lewis, chairman-elect of the defence select committee, warned that an attack would be seen as a modern-day Pearl Harbor and would trigger a ferocious response by the Americans.

Fears that tensions in the Far East could spill over into a deadly war intensified last night after Pyongyang threatened to attack the South Pacific island.

It came hours after Donald Trump promised to unleash 'fire and fury like the world has never seen' unless North Korea drops its threats against the US.

Mr Lopresti, a Tory MP who sat on the defence select committee before the election, told the Mail Online the US president is right to stand up to the rogue regime.

He said: ‘It is obviously a very concerning development indeed and very troubling.

'I think the US President is absolutely right in being robust in his response to provide a deterrent.

‘The US and the UK have a very special relationship, and we are also Nato members.

‘Were he to attack them – as we saw with 9/11 – Article 5 would be evoked which deems an attack on one an attack on all.

'There would be an obligation to do anything we can to support any further action.'

He said it would be 'insanity' for North Korea to launch the strike given America's massive fire power.

Mr Lopresti said: 'The President is right to say don’t even think about it – the response would be unthinkable.

‘I think it is unlikely that a war will happen and that North Korea will act in such a risky or insane way.

'But if any of our allies were attacked we would be obligated to respond.’

Tensions between the US and North Korea have been increasingly strained for months.

Donald Trump warned the North Koreans that they will face 'fire and fury the like of which the world has never seen' ' if they do not drop their nuclear threats to the United States

But they plumbed to a new low after reports emerged which claimed that North Korea would has successfully produced a miniaturized nuclear warhead that can fit inside its missiles.

If correct, it means the country has crossed a key threshold on the path to becoming a full-fledged nuclear power.

Dr Lewis told the Mail Online, that if North Korea fires a nuclear missile at the territory is would be annihilated by the Americans.

He said: ‘If North Korea were to attack Guam it would be a nuclear version of the Pearl Harbor attack.

‘If North Korea were actually to launch a nuclear weapon against an American base the inevitable reaction would be the total annihilation of its capital city and military infrastructure by American nuclear retaliation.

‘Kim Jong-un knows that perfectly well, which is why he is extremely unlikely to launch such an attack in the first place.'

He said the world should concentrate its efforts on a policy of 'military containment of North Korea' as the most 'sensible and safe option.’

Lord West, the former head of the Royal Navy, said Mr Trump’s fiery rhetoric ‘is not helpful’ and that he fears there is a ’50-50’ chance the US could launch a strike on North Korea within the next year.

North Korean despot Kim Jong-un has threatened to launch a military strike on the US territory in the South Pacific. The threat has intensified fears that the two powers could go to war

He said the Americans have made it very clear they will not tolerate North Korea having an intercontinental ballistic missile system that could be used to attack the US.

Admiral Lord West said: ‘So I think there is a 50-50 chance of there being a war within the next 12 months and that is very, very worrying.

‘I think it would be a pre-emptive strike by the Americans. I think it will be a conventional strike - I think they have been put off nuclear by discussions with us and others.

‘It will be a huge conventional strike, but they can’t be sure of hitting all of the nuclear targets, they can’t be sure of killing the president of North Korea and his close aides.

‘And certainly a war might start and Seoul is very near the border, the North Koreans have an army of 1.5 million.

‘It’s all very well chopping the head of a snake off but a snake writhes around for a while before it dies.

‘I think the implications could be huge and so therefore I think it is extremely worrying.’

Lord West called for diplomatic efforts to avoid war.

And he said that while it would be ‘inevitable’ Britain would have to show support for America if war breaks out, we should not back a pre-emptive strike.