As a company director you have a legal obligation to complete a SA100 tax return and relevant supplementary pages. Within the tax return it is highly likely you will need to complete the additional pages for employment if you received a director’s salary (usually the case) and there are sections, within the tax return, that you will need to add income such as dividends. Upon being nominated a company director it is mandatory to complete a SA1 form which is issued by HMRC and this will instigate a notice to complete a tax return as a director.