Paragraph 26 Flight outside controlled airspace
An aircraft flying outside controlled airspace at or above flight level 100 shall remain at least 1,500 metres horizontally and 1,000 feet vertically away from cloud and in a flight visibility of at least 8 km.
Subject to sub-paragraph (b), an aircraft flying outside controlled airspace below flight level 100 shall remain at least 1,500 metres horizontally and 1,000 feet vertically away from cloud and in a flight visibility of at least 5 km.
Sub-paragraph (a) shall be deemed to be complied with if:
the aircraft is flying at or below 3,000 feet above mean sea level and remains clear of cloud and in sight of the surface and in a flight visibility of at least 5 km;
the aircraft, other than a helicopter, is flying at or below 3,000 feet above mean sea level at a speed which according to its air speed indicator is 140 knots or less and remains clear of cloud and in sight of the surface and in a flight visibility of at least 1,500 metres; or
in the case of a helicopter the helicopter is flying at or below 3,000 feet above mean sea level at a speed, which having regard to the visibility is reasonable, and remains clear of cloud and in sight of the surface.