Specific Regulations (and Codes/Guidance) cover certain farm and other land-based activities. Look at some of these laws which particularly affect your organisation.
Regulations spell out what you MUST do - or risk prosecution. Have a look at one regulation relevant to work:
e.g. Manual Handling, Working at Height, Confined Spaces (2), Lifting Operations (LOLER) (1), Work Equipment (PUWER) (17), COSHH (2) COPR (17), Electricity at Work (3). Numbers in brackets equal breaches in agriculture since 1999 (total 90), which also include breaches of Management Regs (8) and HASAW Act (26). For more, see breaches in Agriculture Hunting and Related Services

Approved Codes of Practice (ACOP) is like the Highway Code. This can be quoted in Court but is not used to BRING a case.
e,g Substances that cause occupational asthma, "Green Code" for pesticides.

Guidance Notes are just advice that indicates how to make sure of compliance.
Free Guidance Leaflets from HSE.

All
Asbestos Regulations, Code & Guidance
Prevention of Accidents to Children in Agriculture Regulations (PACAR), (N.Ireland Regs), ACOP and Guidance (pdf)
Certificate of competence explains where specific competences may be required on farms and holdings.

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