PART 6 Survey and certification of ships

23 Prohibition on United Kingdom ships proceeding to sea without an IBWM Certificate
Subject to regulation 40(2) (general provisions on detention) a United Kingdom ship to which this regulation applies must not—
(a) proceed to sea; or
(b) if it is already at sea, remain at sea,
unless an IBWM Certificate has been issued in respect of the ship which is still valid.