a. when authorised by law, b. in respect of employees' contributions to service pension schemes subject to the Company Pensions Act, the Contributory Pension Schemes Act or public service pension schemes, c. when stipulated in advance by a written agreement, d. when a collective pay agreement provides for the withholding of trade union dues including premiums for group insurance linked to trade union membership or contributions to information and development funds or low-income funds, e. in respect of compensation for damage or loss suffered by the undertaking, and caused wilfully or by gross negligence on the part of the employee in connection with the work, when the employee has acknowledged his liability in writing or it has been established by a court decision, or when the employee unlawfully terminates his employment, f. when, owing to current routines for calculation and disbursement of pay, it has in practice been impossible to take account of absence due to work stoppages or lockouts during the accounting period.