Maintenance and use of silencer

(1) No person shall use or cause or permit to be used on a road any vehicle propelled by an internal combustion engine so that the exhaust gases from the engine escape into the atmosphere without first passing through the silencer, expansion chamber or other contrivance required by these Regulations to be fitted. (2) Every such silencer, expansion chamber or other contrivance shall at all times while the vehicle is used on a road be maintained in good and efficient working order, and shall not 126 have been altered in such a way that the noise caused by the escape of the exhaust gases is made greater by the alteration.