On This Day: Korean War starts... and it still hasn’t officially ended

June 25: The Korean War started on this day in 1950 – and 63 years later it still has not officially ended.

The Communist North invaded the South five years after the former Japanese colony was divided between Soviet and American occupation zones.

In response the U.S., which administered the South until it formed its own right-wing government in 1948, sent troops to repel the attack.

They were able to get a United Nations Security Council resolution authorising military intervention due to a USSR boycott and because China was not a member.

The North made massive gains by the time American troops - who accounted for 88% of the 341,000 international soldiers - had arrived at the beginning of July.

The UN forces, which included 14,000 Britons, initially suffered huge losses and had virtually been pushed off the peninsula by September.

But a British Pathé newsreel, which also recorded the battles at the UN General Assembly, shows the Americans quickly making ground again after this.

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Within a month, The North, which was largely supplied by the Soviet Union, had been pushed back to the 38th Parallel, the pre-war border.

By December, UN and South Korean forces, led by U.S. General Douglas MacArthur, had seized the vast majority of territory in the North in a bid to reunify Korea.

But China, whose leader Mao Zedong ordered his People’s Volunteer Army into Korea to fight against 'American aggression' in October, forced the UN back.

By January 1951, the North Korea was back in control of all its former territory and the Chinese had pushed MacArthur’s forces south of the 38th Parallel again.

The Americans gained a little ground once more, but from March onwards the war became a stalemate as the opposing forces reinforced their lines.

The futile deadlock, which nevertheless cost lives, was highlighted by the 1970s U.S. comedy series Mash.

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The war ended with an armistice in July 1953 that established a Demilitarised Zone near the 38th Parallel that, despite its name, is the most heavily militarised border in the world.

The two countries officially remain at war as no peace agreement has been signed.

Since 1953, the South has gone on to become one of the richest countries in the world, while the North – ruled by the same family since 1948 – is one of the poorest.

The secretive North -now headed by Kim Il-sung’s grandson Kim Jong-un - has since launched many small attacks on South Korea and continues to threaten all-out war.

In March this year, the North withdrew from all non-aggression pacts and announced plans to launch a preemptive nuclear strike against the U.S.