For the purposes of this Part an employee shall be taken to be laid off for a week if—
he is employed under a contract on terms and conditions such that his remuneration under the contract depends on his being provided by the employer with work of the kind which he is employed to do, but
he is not entitled to any remuneration under the contract in respect of the week because the employer does not provide such work for him.
For the purposes of this Part an employee shall be taken to be kept on short-time for a week if by reason of a diminution in the work provided for the employee by his employer (being work of a kind which under his contract the employee is employed to do) the employee's remuneration for the week is less than half a week's pay.