A player may decide that he would sooner his unit did not pursue. Normally a unit must pursue if it is able to do so, but the player may attempt to halt the pursuit by making a test against the unit's Leadership (Ld). This represents the unit's leader calling to his troops to hold, while their natural inclination is to run after the enemy and cut them down as they scatter. Roll 2D6, and if the score is equal to or less than the unit's Leadership value then the test is passed and the unit may remain stationary instead of pursuing.
A unit does not have to pursue if it is defending a wall, a hedgerow, a house, or a comparable obstacle or fortification. As pursuing would force the unit to abandon its secure position there is a great incentive to stay put! In this situation, the player can choose to pursue or not as he wishes.