In World War II the two wagons were used to mount 13.5-inch guns, which were capable of engaging targets on the German-occupied Channel coast of France.

It had originally had a 14-inch barrel during World War I, and the last action in which it fired was in 1916 when three rounds completely destroyed the railway station at Arras in France.

After initial training at Catterick Camp in the summer and autumn of 1940, the 11th Super Heavy Battery, under the command of Major Boyle, moved to Kent in early January 1941.

The gun was first fired, for calibration tests, on the morning of 13 February 1941, when the equipment was towed to a stretch of track near the Black Robin public house, Kingston.

In the Kingston and Barham area villagers were warned to open doors and windows, but the blasts were so severe that in many cases houses were damaged.

On 20 June 1941, the "Boche Buster" was inspected by Winston Churchill at Bishopsbourne station, and later that day the Prime Minister viewed the smaller guns at Elham.

In 1944 the army decided that all the guns would be more useful in the Allies' drive towards Germany and they were taken to Salisbury Plain for testing prior to the invasion of Normandy.

[3] Only the gun from the fifth howitzer, named "barrel number one", survives,[4] it was used for artillery testing at MoD Shoeburyness in 1920 before being put into storage at the Royal Arsenal at Woolwich.

[4] After decades in storage, the barrel was put on public display at Larkhill, when the Royal Artillery relocated there in 2008 with the closure of its Woolwich Barracks.