No. While it is beneficial and therefore encouraged, the DPA only requires data controllers to appoint a DPO if they:

• are a public authority;
• if they process personal data on a large scale;
• if they process certain types of personal data;
• if they fall within a prescribed class of controllers;

There is no express prohibition against an employee being appointed as the DPO; however, data controllers must be mindful that their duties as DPO do not conflict with their duties as an employee.