When any person, in this section and §§ 42-1-420 and 42-1-430 referred to as "owner," undertakes to perform or execute any work which is a part of his trade, business or occupation and contracts with any other person (in this section and §§ 42-1-420 to 42-1-450 referred to as "subcontractor") for the execution or performance by or under such subcontractor of the whole or any part of the work undertaken by such owner, the owner shall be liable to pay to any workman employed in the work any compensation under this title which he would have been liable to pay if the workman had been immediately employed by him.