Up to 1871
all hangings in Britain
used the "short drop" where the prisoner
only dropped a few inches and usually died by slow strangulation that could typically take up to 15 minutes
. The more fortunate died due to Vagal reflex (pressure on the Vagal
nerve) which causes death very quickly. Occasionally the prisoner was later revived
even after hanging for half an hour. There are several recorded cases of this where people lived for many years afterwards.
As a result of these incidents a slightly longer drop, of about 12 - 18 inches became normal to ensure that prisoners did not survive. However, this extra drop tended to cause them to suffer a more agonizing death as it was not long enough to break the neck - instead, the force of it tore the neck muscles and sometimes the skin. Hanging using a short drop is still used by some Middle Eastern countries; notably in Iran, Iraq and Libya.
In 1871 hangman William Marwood introduced the "long drop" method which is thought to have been invented by doctors in Ireland. It removed most of the prisoner's physical suffering and made the whole process far less traumatic for the officials who now had to witness it in the confines of the execution cell instead of in the open air. The long drop method was designed to break the prisoners' neck by allowing them to fall a pre-determined distance and then be brought up with a sharp jerk by the rope.
At the end of the drop the body is still accelerating under the force of gravity but the head is constrained by the noose which delivers a massive blow to the back and one side of the neck which - combined with the downward momentum of the body - breaks the neck and ruptures the spinal cord. This is thought to cause instant unconsciousness and rapid death. The drop given was usually between 4 and 10 feet depending on the weight and strength of the prisoner. The actual amount being calculated to provide a final "striking" force of approximately 2200 lbs force (one ton) which - combined with the positioning of the eyelet of the noose normally under the left angle of the jaw (the submental position) - causes fracture and dislocation of the neck usually at the second and third or fourth and fifth cervical vertebrae.