Forcing annual leave
Employers have a statutory right to require employees to take annual leave at their direction, subject to providing staff with notice equal to at least double the length of the leave that you are directing them to take (e.g. 10 days’ notice for five days leave). However, this measure is not likely to achieve any urgent cost savings or alleviate immediate cash-flow pressure as holidays would need to be paid.
Clearly, annual leave can be taken on furlough so you could have staff on furlough and annual leave.