Page "Semi-trailer truck" Paragraph 30

Vehicles heavier than 44, 000 kg ( 97, 000 lb ) are permitted on UK roads but are indivisible loads, which would be classed as abnormal ( or oversize ).

Such vehicles are required to display an STGO ( Special Types General Order ) plate on the front of the tractor unit and, under certain circumstances, are required to travel by an authorised route and have an escort.