Common carriers stand in situation of insurers of the goods, not only against the disappearance or destruction, but against all forms of damage to the goods except few limitations mentioned above.
Nugent v Smith (1875) 3 Asp MLC 87 per Brett J. at 89-91:
A shipowner who offers to carry the goods of all comers in a general ship or who runs a line of ships from port to port habitually carrying all goods brought to him is a common carrier.
Per Avory J in Watkins v Cottrell (1915) 52 L. R. 91:
I think it well to state what I understand by the term "common carrier." The following definition, which I take from a well-known text-book Macnamara on Carriers by Land, 2nd ed., p. 11, seems to me to be accurate:
A common carrier is a person who undertakes for hire to transport from a place within the realm to a place within or without the realm the goods or money of all such persons as think fit to employ him. To render a person liable as a common carrier he must exercise the business of carrying as a public employment, and must undertake to carry goods for all persons indiscriminately, and hold himself out, either expressly or by course of conduct, as ready to engage in the transportation of goods for hire as a business, not merely as a casual occupation pro hac vice.