While in the most serious cases mounting an investigation is usually mandatory, there are other occasions where it is less clear-cut or when it is concluded that an investigation would not fulfil RAIB's objectives to improve safety or prevent future accidents. 2021 December 29, Paul Stephen, “Rail's accident investigators”, in RAIL, number 947, pages 30–31:
In previous years Penryn Town Council has used Falmouth Town Council to fulfil the parks contract and glyphosate had been used, councillor Debra Clegg confirmed. 2026 January 14, Lisa Young, “Council delays decision about weedkiller use”, in BBC, archived from the original on 16 Jan 2026:
It is recorded that this remarkable prophecy, now largely fulfilled, was received with much merriment—an undeserved fate. 1955 November, G. Machell, “Railway Development at Aylesbury - 1”, in Railway Magazine, pages 741-742: