Immediate Employer

"Immediate Employer" in relation to employees, employed by or through him, means a person who has undertaken the execution, on the premises of factory or an establishment to which this Act applies, or under the supervision of the principal employer or his agent, of the whole or any part of any work, which is ordinarily part of the factory or establishment of the principal employer or is preliminary to the work carried on in, or incidental to, the purpose of any such factory or establishment, and includes a person by whom the services of an employee, who has entered into a contract of service with him are temporarily lent or let on hire to the principal employer.