27.—(1) This Article applies in the case of a vehicle the use of which on roads otherwise would be authorised by Article 15, 19, 21 or 23 where the overall width of the vehicle or, if it is used for carrying a load, where the overall width of the vehicle together with the width of any lateral projection of its load, exceeds 5 metres.
(2) Subject to the provisions of paragraph (3) a vehicle mentioned in paragraph (1) shall be used only—
(a)for the purpose of making such a journey between specified places as the Department may have approved by notice in writing given to the user of the vehicle and only at such times (if any), on such a date or dates (if any) and on such a route (if any) as the Department may have specified in the said notice, or as the Chief Constable may have specified, in relation to the use of the vehicle, in a direction given to the user of the vehicle; and
(b)if the notice referred to in sub-paragraph (a) is carried on the vehicle at all times while it is being used for the purpose of making the journey for which the Department’s approval has been given.
(3) Where the effect of any such direction as is mentioned in sub-paragraph (a) of paragraph (2) is to vary, in relation to time, a date or a route of the journey approved by the Department under that sub-paragraph, the time, the date or dates or the route of the said journey, the vehicle shall not be used in accordance with that direction unless the Department has given its further approval that the vehicle shall be so used.