The Far East was plunged into more uncertainty as the UK slept, with Japanese residents ordered to take shelter.

A rocket fired from North Korea, the fifth missile launched this week, passed over the nation's airspace in a stark reminder of the tensions that still exist in the region.

With much of the world focused on the war in Ukraine, the test adds further uncertainty to a fragile-seeming world.

Here's what you need to know about the latest developments.

What happened?

At around 7.22am this morning North Korea launched a ballistic missile which travelled over Japan.

Residents were warned to take cover and look out for falling debris, and the weapon crashed into the sea around 22 minutes later.

The missile was not armed with a nuclear device and no-one was harmed.

Why did North Korea launch the missile?

This is the first time the North has fired a missile over Japan since 2017 and it comes at a time of escalating tensions in the region.

South Korea, Japan and the United States last week resumed joint naval exercises for the first time since, you guessed it, 2017. It's fair to assume this is Kim Jong-Un's response to that.

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The North Korean leader has long believed the three countries are preparing for war on his own nation, which is still technically at war with the South following the armistice of 1953 which saw the peninsula divided.

There have been no direct military confrontations since then but with no peace treaty signed the countries are still formally at war.

How much of a threat is North Korea?

This missile travelled further than any previous missile launched by the DPRK (to give it its formal name), travelling over 1,000 miles and reaching the height of the International Space Station.

Its range means the North could, in theory, hit the U.S overseas territory of Guam.

The Herald: North Korean leader Kim Jong-UnNorth Korean leader Kim Jong-Un (Image: Newsquest)

Will there be nuclear tests?

That's very likely. The last time Japan, South Korea and the U.S conducted exercises, the North fired two missiles over Japan and conducted a nuclear test a week later.

They had already test-fired two short-range ballistic missiles, which landed in the sea between the Korean peninsula and Japan, and a nuclear test would likely be the next step.

The last test, in 2017, saw the DPRK claim to have detonated a hydrogen bomb that could be fitted to an intercontinental ballistic missile - a step up from the conventional atom bomb.

Is that true?

North Korea is famously secretive so there's no way of knowing for sure.

Developing the H bomb means moving from a fission to a fusion device and it's not thought any country with those capabilities would help the DPRK with that technology.

It's been suggested that what they tested was instead a fusion-boosted fission device - essentially a halfway house.

However, Tom Plant, director of proliferation and nuclear policy at the Royal United Services Institute said at the time: "The North Koreans do bluff sometimes, but when they make a concrete claim about their nuclear programme, more often than not it turns out to be true."

The Herald: North Korean leader Kim Jong-UnNorth Korean leader Kim Jong-Un (Image: Getty)

What happens next?

The ramped-up missile testing has been condemned as "dangerous and reckless" by the UN Security Council and been dubbed "violent behaviour" by Japan's Prime Minister.

For their part, the North would say that the resumption of naval exercises is provocation on the part of Japan, the U.S and South Korea.

All-out war is unlikely, with the DPRK likely using recent missile launches to emphasise its military capability in the event of an invasion - something the three allied countries have repeatedly said they have no intention of doing.

A historic summit in 2018 saw the leaders of both the North and South commit to working toward a treaty to formally end the war but recent escalations make that unlikely.

It looks like the uneasy stalemate will continue for some time yet.