The Merchant Shipping (Submersible Craft Construction and Survey) Regulations 1981
These Regulations prohibit manned mobile submersible craft (except diving bells) and supporting equipment from operating in United Kingdom waters or from ships which are registered in the United Kingdom or are British ships, without a valid safety certificate issued by the Secretary of State after a satisfactory survey (Regulation 3(1)). Application for the initial survey of the submersible craft and for the supporting equipment must be accompanied by the documents relating to the construction requirements specified in Schedule 1 for submersible craft and in Schedule 2 for one man submersible craft, atmospheric diving suits and supporting equipment (Regulation 3(2)) and they must each comply with the construction critieria specified in Schedule 3 (Regulation 3(3)). The safety certificate will usually be valid for two years (Regulation 4(1)) but may be suspended or revoked (Regulation 5).