The tunnel was built as the rich man who owned the land didn't want his view from his mansion to be ruined by a railway. Since he had a lot of money the tunnel was built.
During WWII the railway was closed to passengers and the military used it for transporting military cargo, but Bourne Park Tunnel had been used to store a massive Railway Gun called Boche Buster. The gun could fire 1.4 ton shells over a 12 mile distance.
Today the two tunnel portals have been blocked by a metal fence and the trackbed in the cuttings on both sides of the tunnel are overgrown.