The army has trained at Otterburn since 1911 when field guns were horsedrawn.
By 1938 tracked vehicles were being used but would often get stuck in the soft peaty ground.
In 1969 Otterburn was being used by infantry units flying ground attack aircraft with guided missiles: it had become the UK's second largest military training area after Salisbury Plain.
With Salisbury Plain operating at maximum capacity in 1992, the MOD decided to shift AS90 self propelled guns and multiple launch rocket systems to Otterburn.
The 1997-8 public inquiries were critical: 'If the MOD had lost, they'd never have been able to train in another national park. Multiple launched rocket systems can only be fired at Otterburn, ' says WYG project manager John Gledhill.