The first major trial took place at Hatfield Park on 29 January 1916. A series of trenches and obstacles had been dug by the 3rd (Mid Herts) Battalion of the Hertfordshire Volunteer Regiment with help from a company of Royal Engineers. The tank crews were provided by men from Squadron 20 of the Armoured Car Division of the Royal Naval Air Service. The trial was divided into 3 parts. The descriptions of these 3 parts below are taken from Sir Albert Stern’s book The Log-book of a Pioneer.
Part I – Official Test.
1. The machine will start and cross the obstacle specified ie a parapet 4 feet 6 inches high and a gap 5 feet wide.
Part II – Test approximating to Active Service.
2. It will then proceed over the level at full speed for about 100 yards, and take its place in a prepared dug-out shelter from which it will traverse a course of obstacles approximating to those likely to be met with on service.
3. Climbing over British defences (reduced for its passage) it will-
4. Pass through the wire entanglement in front;
5. Cross two small shell craters, each 12 feet in diameter and 6 feet deep;
6. Traverse the soft, water-logged ground round the stream, climb the slope from the stream, pass through the German entanglement.
7. Climb the German defences.
8. Turn round on the flat and pass down the marshy bed of the stream and climb down the double breastwork.
Part III – Extra Test if required
9. The “tank” will then, if desired, cross the larger trench and proceed for half a mile across the park to a piece of rotten ground seamed with oil trenches, going down a steep incline on the way.