Trench storming parties should kill or drive back the hostile occupants
of a trench as quickly as possible, clear as much of the enemy trench
as has been ordered, and then hold the portion cleared with as small
loss as possible to themselves. It must be remembered that in trench
clearing, and especially in deep and narrow trenches, only the head of
the attacking party can directly kill, and seldom more than one man
can throw at a time. Therefore it is essential that a constant supply
of grenades reaches the thrower and that the places of casualties are
automatically filled by reinforcements. Men must be trained until they
can do this either by day or at night time.
=Advance.= Movement is rapid until contact with the enemy is obtained.
Once contact is established it must be maintained and pressed home.
A retreating enemy must be given no time to re-establish a defensive
attitude, corners must be worked carefully and bays and straight
pieces of trench rushed. The bayonet men will complete the work of
the grenades and see that the carrier and thrower will meet with no
opposition on their way to new throwing position. The effect of a
grenade bursting in a confined space like a trench is tremendous, and
though it may not kill it will stun or shock the hostile occupants, and
if the bayonet men follow up rapidly they will meet with very little
resistance.
=Casualties.= Every man must be trained to take up the duties of any
other man in his squad. They do not necessarily keep to their own
squads; the squads in rear of the attacking squad may be looked on as
a reserve squad for the one in front. Thus, Casualty first squad. The
thrower No. 3 is reinforced by the first thrower of the second squad,
and so on.
=Side Trenches.= When a side trench is met with, the leading squad will
go up and clear it. The second half will remain at the junction until
first returns, then the second squad will continue advance in original
direction of the attack.
=Blocking and Barricades.= For blocking captured trenches, etc., see
Manual of Field Engineering, Wire Entanglements, Hurdles, etc.