The financial year for a new company starts on the day of incorporation; you have a legal responsibility to immediately contact HMRC and keep accounting records - even if not trading.
companies house responsibilities
A private company filing its first accounts must do so within 21 months of the date of incorporation, and after that within 10 months of the company’s Accounting Reference Date (ARD). The company’s first ARD is a year after the last day in the month of its incorporation. Dormant companies have special rules.
Key information about activities, directors, shareholders etc on what is known as the Legal Return Date (LRD) or “made up” date must be sent each year (usually the anniversary of the incorporation of the company, or the anniversary of the made up date of the previous annual return registered at Companies House, if different.) Information must be returned within 28 days of the LRD with amendments.
Limited companies must complete a corporation tax return every year and supply a set of accounts. CT is normally paid within nine months and one day of the end of a company’s financial year. You will also need to operate a PAYE system to collect and pay income tax and NIC from employees – including company directors.
Company directors, employed by their own company must also send self assessment tax returns (30th September each year if HMRC to calculate tax or 31st January otherwise). Partners pay their own tax by making two payments on account - deadlines are 31st January and 31st July each year.