The Nimrod Review - Official Documents

9.22
9.23
Chapter 9 – Background to Safety Cases
cost” 38 and that a computation must be made in which the quantum of risk is placed on one scale and the
sacrifice, whether in time, money or trouble, involved in the measures necessary for averting the risk is placed in
the other; and that, if it be shown that there is a gross disproportion between them, the risk being insignificant
in relation to the sacrifice, then the person upon whom the duty is laid discharges the burden of proving that
compliance was not reasonably practicable. 39
The HSE has endorsed this test of ‘gross disproportion’, namely, that in any assessment as to whether risks have
been reduced to ALARP, measures to reduce the risk can be ruled out only if the sacrifice involved in taking
them would be grossly disproportionate to the benefits of the risk reduction. 40 The HSE summarises matters by
stating:“Thus, determining that risks have been reduced ALARP involves an assessment of the risk to be avoided,
of the sacrifice (in money, time and trouble) involved in taking measures to avoid that risk, and a comparison
of the two.”
The ‘R’ in ALARP thus has a financial, temporal and trouble component.
Development of Safety Cases in the RAF
Management Services (Organisation) Division Study (1994)
9.24
9.25
9.26
The requirement for Safety Cases within the MOD can be traced back to the Management Services (Organisation)
Division Study No. 773 – Equipment Safety Assurance, dated March 1994 (Man S (Org) Study), which in large
part grew out of the findings and conclusions of the Piper Alpha report.
The Man S (Org) Study was sponsored by the Deputy Under Secretary of State (Defence Procurement) (DUS(DP))
and had a number of specific tasks which included: (1) examining the existing and planned arrangements for
ensuring that equipment procured by the Procurement Executive (PE) for its customers was safe for use by
reference to contemporary standards and legislative support; and (2) establishing whether such arrangements
reflected latest thinking and best practice in safety and risk management and took account of statutory
requirements and applicable MOD standards governing safety in Defence equipment. 41
The Man (S) Org Study found that, in relation to procurement strategy, there were some concerns that safety
was not addressed as a specific item requiring attention as part of the overall process. The central concerns
related to the lack of visibility and accountability regarding equipment assurance and the lack of a coherent
safety policy. These concerns gave rise to the following recommendations (amongst others): 42
9.26.1 That safety management should be addressed as part of the procurement strategy process.
9.26.2 The establishment of a safety directorate to define policy, set standards, give advice and liaise with,
for example, the HSE. The Man S (Org) Study shared Lord Cullen’s view that a ‘goal-setting’ approach
should be adopted.
9.26.3 The creation of a central safety management office and safety management board.
9.26.4 The implementation of a Safety Case regime in the procurement process, its objective being “to provide
a well organised and resourced justification of the acceptability of the System’s safety”. The Man (S)
Org Study noted that the essential features of a Safety Case were that it must fully describe the system,
identify the hazards, identify the risks and indicate the safeguards and describe the safety management
system arrangements.
9.26.5 The development of Def-Stan 00-56 to address the whole safety system (see further below).
38 Per Tucker LJ, at page 710.
39 Per Tucker LJ, at page 712. And see further the report of Adelard on “Numerical Criteria for Airworthiness” dated 30 September 2002, produced
for ALTG.ADRP1 under contract MAP2b/1351.
40 HSE Document“Principles and guidelines to assist HSE in its judgment that duty-holders have reduced risk as low as reasonably practicable”,
paragraph 24.
41 Man S (Org) Study, at pages A1-A2.
42 See the Summary of Recommendations at page 85 of the Man S (Org) Study.
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