The Dockyard Port of Plymouth Order 1999


7.  No person shall swim on the surface or underwater within—

(a)100 metres of the walls, slipways or boundaries of Her Majesty’s Dockyards or other Crown Establishments;

(b)150 metres of any of Her Majesty’s vessels;

(c)any area where anchorage is prohibited under regulation 22,

save with the permission of the Queen’s Harbour Master.