In terms of health and safety, absolute duties are never phrased as X to do Y. But rather, absolute duties are expressed by the term “shall”.

Absolute duties must be complied with. Even if that means that an activity can no longer be carried out.

Often known as strict liability, absolute duties are at the top of the hierarchy of duties.

The next on the hierarchy of duties are qualified duties. Qualified duties are often phrased phrased as:

  • So far as is practicable
  • So far as is reasonably practicable

The hierarchy of duties

  1. It shall be the duty… (absolute)
  2. It shall be the duty so far as is practicable… (qualified)
  3. It shall be the duty so far as is reasonably practicable… (qualified)

So far as is practicable

So far as is practicable is used to qualify that a duty must be complied with in line with current knowledge and understanding.

This implies that we must assess whether or not it is physically possible to do at the time.

The assessment must not take into consideration:

  • The time it would take
  • The trouble involved
  • Or, the cost

Such judgements must be kept on record and be reviewed periodically. What might not be achievable today, could be in the future.

So far as is reasonably practicable

The addition of “reasonably” to this statement indicates that there is a balance to be achieved. So far as is reasonably practicable allows for an assessment to consider the time, effort and cost.

A balance must be assessed against the risk and this calculation has to be made before any accident occurs. This ensures the the assessment is based on the balance of risk against the cost in terms of time, trouble and money.

If there are very high risks, then the duty must be performed irrespective of the cost.

It is the risk that will determine whether or not the costs involved are justified. There can be no allowance made for the size, nature or profitability of the business.

A judges summary

These points were nicely summarized in a leading case law decision, in which the judge stated that:

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, whether in money, time or trouble involved in the measures necessary to avert the risk is placed in the other; and that, if it is shown that there is a gross disproportion between them, the risk being insignificant in relation to the sacrifice, the person upon whom the duty is laid discharges the burden of proving that compliance was not reasonably practicable. This computation falls to be made at a point of time anterior to the happening of the incident complained of.

Edwards v National Coal Board (1949)