Edwards v National Coal Board

Edwards v. National Coal Board was an important case in English case law. The 1949 case revolved around whether it was "reasonably practicable" to prevent even the smallest possibility of a rock fall in a coal mine.

Underlying facts
Mr Edwards died in an accident after the supporting structure for the mine roadway gave way. The National Coal Board argued that it was too expensive to shore up every roadway in all of the mines.

The case turned when it was decided that it was not 'all of the roadways' that needed shoring up; just the ones that required it. In essence this established the need to carry out a risk assessment to establish the cost, time and trouble to mitigate a risk balanced against the risk of any harm it might cause.

Asquith stated in his judgement: Reasonably practicable is a narrower term than ‘physically possible’ and implies that a computation must be made... in which the quantum of risk is placed in one scale and the sacrifice involved in the measures necessary for averting the risk (whether in time, trouble or money) is placed in the other and that, if it be shown that there is a great disproportion between them – the risk being insignificant in relation to the sacrifice – the person upon whom the obligation is imposed discharges the onus which is upon him.

Significance
This case established the concept of "reasonable practicability." The Court of Appeal decided that "reasonably practicable" was a more narrowly defined phrase than what was "physically possible." This allowed for the creation of equations that measured the risk present in a given situation against the reasonable practicability of mitigating that risk. In other words, the equation asked if averting the risk was worth the effort it took to negate that risk. In addition, the court in Edwards determined that the size and wealth of the company should have no bearing on such decisions.