The answer to this is likely to be no. Most employers will have specific arrangements in place for booking leave and this will usually require you to give a certain amount of notice of any request to take annual leave. Any such request will be subject to your employer's approval.
It is likely that you will also have to complete some kind of leave booking form as well. Your employer may need certain minimum levels of staffing to run the business and, therefore, granting requests for annual or unpaid leave would need to be coordinated and planned.
If you take holiday without following your employer’s procedures for booking annual leave, you run the risk of disciplinary action.