The mastermind behind North Korea's missile programme has been revealed as a middle-aged scientist who was promoted by Kim Jong-un after successfully launching a satellite into space.

Kim Jong-sik, a technical expert with more than 20 years of experience, is the brains behind the rogue state's nuclear-armed intercontinental ballistic missiles.

He now holds North Korea's highest honour, the Order of Kim Jong-il, and is a top figure in the the country's munitions industry department.

The mastermind behind North Korea's missile programme has been revealed as middle-aged scientist Kim Jong-sik (circled)

His next launch could be just hours away, with South Korean intelligence warning that a fresh ICBM is being readied for blast off.

Michael Madden, a leading authority on Pyongyang's elite who works with the 38 North watchdog, called the rocket scientist a 'key figure' in the missile programme.

Mr Madden said: 'He's important – pretty much the most consistent person at these missile tests and the things that are related to the defence industry.

'He is a guy that's helped them identify certain technical problems or reach certain technical benchmarks and that's a critical thing.

'That's how he got his current position – because he was involved in the successful launch of the Unha-3 space rocket in December 2012.

Kim Jong-sik (seen over Kim Jong-un's shoulder) is a technical expert with more than 20 years of experience

The mastermind (pictured on the right of Kim Jong-un) now holds North Korea's highest honour, the Order of Kim Jong-il

Building an armoury: North Korea's test launch of a Hwasong-12 intermediate range missile in Pyongyan

'They tried a space launch in April 2012 and it failed after 10 seconds – so they got rid of some people and then, in December 2012, Kim Jong-sik was one of the lead guys.

'He moved from being a sort of a mid-level guy to being one of the lead people… and that's where his career gets this big bump.

'Then about a year-and-a-half later he all of a sudden shows up as a deputy director of North Korea's munitions industry department.'

In North Korea, deputy directors tend to have more power than actual directors, Mr Madden said – and though several people share the title, Kim Jong-sik is the only technical wizard.

'There are people that have the position – they have the job title – but have other responsibilities,' said Mr Madden. 'They don't even work in the building itself, they work elsewhere.

'Kim Jong-sik is one of five people that have that title... but he is the guy that is involved because he is an aeronautics engineer and is involved in missiles and space and rocket engines and thrust.'

Kim Jong-sik (pictured left) is a top figure in the the country's munitions industry department

Kim Jong-sik (pictured second from right) is North Korea's top an aeronautics engineer

Kim Jong Un supervised a ballistic rocket launching drill of Hwasong artillery units earlier this year

When Pyongyang tested its first ICBM in July, bringing the continental US within range for the first time, North Korean propaganda named Kim Jong-sik among the leader's entourage.

He was also on hand for the second ICBM test later that month, as well as last week when Kim Jong-un fired a missile that overshot the Japanese island of Hokkaido.

Yet the rocket scientist, who's believed to be in his 50s, wasn't born into the North Korean elite – he was promoted in a bid to boost the pace of missile development.

'He's one of these people that Kim Jong-un kind of plucked from obscurity and brought him into the fold,' said Mr Madden.

'And that's because of his accomplishments, not due to him having been the cousin of somebody or something like that, which happens sometimes in North Korea.

'Kim Jong-un has been very good actually about promoting people that didn't have the traditional patronage ties.'