buildings, some of which had been standing for over ten years, and to form the ramparts, the six very basic gun emplacements, two to each flank and a pair overlooking Luton Valley. Even so no armament is on record as ever having been issued to Fort Luton other than that brought in by units participating in the Annual Militia and Volunteer camps. The final act of engineering was the installation of the drawbridge in 1892 which is a rare type of rolling bridge and possibly the only one still left in the UK Siege trials For the next thirteen years the fort was used for summer camps and, on alternate years, the Chatham Siege Trials. The final one in 1907 was the largest in both scope and number of men employed, and was in effect a rehearsal for a major war. Three breaches were made in the counterscarp wall and three "camoflets" were exploded in the moat bottom. The "defenders" dug a large counter-mine shaft outwards from the base of the moat. The breaches were repaired in 1908 by infilling with flint rubble, but the main counter-mine shaft was left. As a result of all this, in 1914, the north scarp wall shifted slightly and had to be braced by a steel joist from off the top of the counterscarp wall. The damage to the moat and the subsequent repair are still visible. Layout of the fort The Fort consists of a D-shaped rampart with prepared earthen gun positions for movable armament, two to each flank. The front parapet was prepared for infantry defence. Beneath the rampart are four ammunition stores with vertical lifts to handling rooms on the rampart above. To the rear of the main rampart at the gorge of the fort is a series of eight casemated barrack rooms serving as accommodation for the garrison, ammunition stores and general stores. All are constructed of concrete with an earth covering. At each end of the casemates is a tunnel to the ammunition stores. The casemates formed a longitudinal parados protecting the ramparts from reverse fire. The main entrance to the fort was over the rolling bridge at the centre of the casemates. The ditch surrounding the fort was intended to be dry. The ditch The ditch is lined with concrete on both the scarp and counterscarp faces. It has on both faces a slight batter of three degrees