The provision of such time off work is unusual. However, there is a legal right to request time off work for individuals working in big organisations (250 employees or more) and smaller employers may be persuaded to voluntarily follow the same procedure. You will need to discuss the proposition with your employer and demonstrate why they would benefit.
Also, find out whether your employer has a training and development policy which provides for sponsored sabbaticals (i.e. a period of time for which staff are allowed to stop their usual work, in order to study or travel, usually while continuing to be paid), which might meet your needs.
If no such policy exists, your employer might be prepared to provide such an opportunity, but without pay.
If that is the case, you would need to find out how you might financially support yourself and your family for the duration of the course.
If your employer is not prepared to support your request, don't give up - consider ways of completing the programme while maintaining your employment.
Also, if other work colleagues have been granted such time off for study purposes, and you have not - ask for an explanation. If you don't receive a satisfactory answer, you may feel aggrieved and wish to pursue your claim using your organisations grievance procedure.
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