16.—(1) If the Inland Revenue determine that the code for use by an employer in respect of an employee for a tax year remains the same as at the previous 5th April, the Inland Revenue need not issue a code to the employer.
(2) If for any tax year the employer does not receive a code for an employee who was in that employer’s employment on the previous 5th April, the code which applied on that date is treated as having been issued by the Inland Revenue for the tax year in question.