It depends on your shareholding. If you own more than 15% of the Company, you will be a proprietary director and considered self-employed. You would still be entitled to the PAYE tax credit in your other employment however. If you are also registering as an employee of the company you'll be a director of, you can elect to split your personal tax credit whatever way you wish between the two companies. It's my understanding that you wouldn't be entitled to the new self-employed tax credit if you are already claiming the PAYE tax credit from the other employment.