Part 1 & 2: The rocket that could have changed the course of WW2

• Watch part one of Derek Johnson's report below:

In September 1944, a deadly weapon began to be launched on Britain, a long-distance missile that travelled at the speed of sound and took just minutes from launch to impact.

The V2 was the most advanced weapon created by the Nazis. The missile reached Berkshire and Hampshire, and if all had gone according to plan it could have destroyed communities across the South, and even lost the Allies the Second World War.

In France, La Coupole, now a museum, was meant to be the main launch site for the V2 rockets.

It was designed to push to the edge of Space, before hurtling to the ground with a ton of explosives.

The plan was to assemble the rockets, take them outside via a railway track and fire them round the clock at Britain's cities.

In the end La Coupole was never used in anger. The site and tunnels were abandoned just after the Allies landed in Normandy on D-Day. The V2s that were launched came from mobile sites in Holland and although the damage was catastrophic, mainland Britain was spared the full horror of a mass, constant bombardment by rocket.

Historian Rebecca Blackburn says: "It could have changed the war. Given a lot more money and a few more years. You see in 10 to 20 years after the war the intercontinental ballistic missiles of America and Russia. They were based directly off the V2 so that's a taste of what could have happened if Germany had poured even more money and resources into it.''

Although almost 3,000 people in Britain were killed in V2 strikes, many more concentration camp workers died making the rockets at a site in Germany.

The scramble for technology after the war saw the main scientists behind the V2 went on to play a major part in the Apollo programme that put the first human on the Moon.

• Watch part two of Derek Johnson's report below: