A tourniquet (20, 220, 320, 420) for application to a patient's limb in an emergency situation, and a method for its application. The tourniquet includes a tension-sensing mechanism (26, 100, 190, 240) used to establish a baseline tension in a loop around an injured limb, and a tension-increasing mechanism (58, 108, 140, 160, 260) to tighten the tourniquet as required beyond the baseline tension. The tension- sensing mechanism may be incorporated in a buckle (26, 100, 190, 240) in which a pin (40, 40', 193, 250) can protrude to engage and maintain tension in a strap member (22, 228) which is part of the loop. A latch (204, 210, 206, 312) may be incorporated in the buckle to keep it in a condition in which the pin protrudes to engage the strap and maintain the baseline tension. A release tab (194, 314) operable to release the latch is located where it is protected against inadvertent operation.
