The Road Vehicles (Construction and Use) Regulations 1986 S100(2)
Maintenance and use of vehicle so as not to be a danger, etc
(2) The load carried by a motor vehicle or trailer shall at all times be so secured, if necessary by physical restraint other than its own weight, and be in such a position, that neither danger nor nuisance is likely to be caused to any person or property by reason of the load or any part thereof falling or being blown from the vehicle or by reason of any other movement of the load or any part thereof in relation to the vehicle.
42 Breach of other construction and use requirements.
A person who—
(a)contravenes or fails to comply with any construction or use requirement other than one within section 41A(a) or 41B(1)(a) [F2or 41D] of this Act, or
(b)uses on a road a motor vehicle or trailer which does not comply with such a requirement, or causes or permits a motor vehicle or trailer to be so used,
is guilty of an offence.