Can an employer make an employee take their accrued but untaken holidays during their notice periods where there is no express contractual provision?

Section 23 of the Organisation of Working Time Act 1997 (the “Act”) provides that employers must pay employees in lieu of accrued but untaken annual leave in respect of their last year of employment. 

The Act does not, however, specify whether employers can oblige employees to take the annual leave during the notice period, and in the absence of a contractual provision, the general provisions in relation to annual leave in the Act will be relevant. 

Section 20 of Act provides that the times at which annual leave is granted to an employee shall be determined by the employer having regard to work requirements and subject.
The section provides that if determining that an employee is