(1)In this Part—
" Commissioner" means a Social Security Commissioner and includes a tribunal of Commissioners constituted under section 116 of the principal Act;
" contract of service " (except in paragraph (a) of the definition below of " employee ") includes any arrangement providing for the terms of appointment of an employee ;
" employed earner's employment " has the same meaning as in die principal Act;
" employee " means a person who is—
gainfully employed in Great Britain either under a contract of service or in an office (including elective office) with emoluments chargeable to income tax under Schedule E; and
over the age of 16 ;
but subject to regulations, which may provide for cases where any such person is not to be treated as an employee for the purposes of this Part and for cases where any person who would not otherwise be an employee for those purposes is to be treated as an employee for those purposes;
" employer ", in relation to an employee and a contract of service of his, means the secondary contributor (within the meaning of section 4 of the principal Act) in relation to any earnings paid, or to be paid, to or for the benefit of that employee under that contract;
" insurance officer " means an officer appointed under section 97(1) of the principal Act;
" local office " means any office appointed by the Secretary of State as a local office for the purposes of this Part;
" local tribunal " means a tribunal established under section 97(2) of the principal Act;
" maternity allowance " means an allowance payable under section 22 of the principal Act;
" pensionable age " means, in the case of a man, 65 or, in the case of a woman, 60; " period of entitlement" has the meaning given by section 3 of this Act;
" period of incapacity for work " has the meaning given by section 2 of this Act;
" period of interruption of employment" has the same meaning as it has in the principal Act by virtue of section 17(1)(d);
" prescribed " means prescribed by regulations ;
" primary Class 1 contributions " and " secondary Class 1 contributions" have the same meaning as in the principal Act;
" qualifying day " has the meaning given by section 4 of this Act;
" week " means any period of seven days.
(2)For the purposes of this Part an employee's normal weekly earnings shall, subject to subsection (4) below, be taken to be his average weekly earnings in the relevant period under his contract of service with the employer in question.
(3)For the purposes of subsection (2) above, the expressions " earnings " and " relevant period " shall have the meaning given to them by regulations.
(4)In such cases as may be prescribed an employee's normal weekly earnings shall be calculated in accordance with regulations.
(5)Without prejudice to any other power to make regulations under this Part, regulations may specify cases in which, for the purposes of this Part or of such provisions of this Part as may be prescribed—
(a)two or more employers are to be treated as one ;
(b)two or more contracts of service in respect of which the same person is an employee are to be treated as one.
(6)Regulations may provide for periods of work which begin on one day and finish on the following day to be treated, for purposes of this Part, as falling solely within one or other of those days.
(7)In this Part any reference to Great Britain includes a reference to the territorial waters of the United Kingdom adjacent to Great Britain.